1
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Chin DD, Lentink D. Birds both avoid and control collisions by harnessing visually guided force vectoring. J R Soc Interface 2022; 19:20210947. [PMID: 35702862 PMCID: PMC9198520 DOI: 10.1098/rsif.2021.0947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/16/2022] [Indexed: 11/12/2022] Open
Abstract
Birds frequently manoeuvre around plant clutter in complex-structured habitats. To understand how they rapidly negotiate obstacles while flying between branches, we measured how foraging Pacific parrotlets avoid horizontal strings obstructing their preferred flight path. Informed by visual cues, the birds redirect forces with their legs and wings to manoeuvre around the obstacle and make a controlled collision with the goal perch. The birds accomplish aerodynamic force vectoring by adjusting their body pitch, stroke plane angle and lift-to-drag ratios beat-by-beat, resulting in a range of about 100° relative to the horizontal plane. The key role of drag in force vectoring revises earlier ideas on how the avian stroke plane and body angle correspond to aerodynamic force direction-providing new mechanistic insight into avian manoeuvring-and how the evolution of flight may have relied on harnessing drag.
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Affiliation(s)
- Diana D. Chin
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
- Faculty of Science and Engineering, University of Groningen, Groningen, Groningen, The Netherlands
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2
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Matyjasiak P, López-Calderón C, Ambrosini R, Balbontín J, Costanzo A, Kiat Y, Romano A, Rubolini D. Wing morphology covaries with migration distance in a highly aerial insectivorous songbird. Curr Zool 2022. [DOI: 10.1093/cz/zoac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
According to classical prediction of aerodynamic theory, birds and other powered fliers that migrate over long distances should have longer and more pointed wings than those that migrate less. However, the association between wing morphology and migratory behavior can be masked by contrasting selective pressures related to foraging behavior, habitat selection and predator avoidance, possibly at the cost of lower flight energetic efficiency. We studied the handwing morphology of Eurasian barn swallows Hirundo rustica from four populations representing a migration distance gradient. This species is an aerial insectivore, so it flies extensively while foraging, and may migrate during the day using a ‘fly-and-forage’ migration strategy. Prolonged foraging flights may reinforce the effects of migration distance on flight morphology. We found that two wings’ aerodynamic properties – isometric handwing length and pointedness, both favoring energetically efficient flight, were more pronounced in barn swallows from populations undertaking longer seasonal migrations compared to less migratory populations. Our result contrast with two recent interspecific comparative studies that either reported no relationship or reported a negative relationship between pointedness and the degree of migratory behavior in hirundines. Our results may thus contribute to confirming the universality of the rule that longer migrations are associated with more pointed wings.
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Affiliation(s)
- Piotr Matyjasiak
- Museum and Institute of Zoology Polish Academy of Sciences, Wilcza 64 , PL-00-679 Warsaw, Poland
- Institute of Biological Sciences, Cardinal Stefan Wyszyński University in Warsaw, Wóycickiego 1/3 , PL-01-815 Warsaw, Poland
| | - Cosme López-Calderón
- Departamento de Zoología, Facultad de Biología, Edificio Verde , Avda. de Reina Mercedes s/n, E-41012 Sevilla, Spain
- Department of Wetland Ecology, Estación Biológica de Doñana CSIC, Americo Vespucio s/n , E-41092 Seville, Spain
| | - Roberto Ambrosini
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26 , I-20133 Milan, Italy
| | - Javier Balbontín
- Departamento de Zoología, Facultad de Biología, Edificio Verde , Avda. de Reina Mercedes s/n, E-41012 Sevilla, Spain
| | - Alessandra Costanzo
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26 , I-20133 Milan, Italy
| | - Yosef Kiat
- Israeli Bird Ringing Center (IBRC), Israel Ornithological Center, Society for the Protection of Nature in Israel , Hanegev 2, Tel-Aviv, Israel
| | - Andrea Romano
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26 , I-20133 Milan, Italy
| | - Diego Rubolini
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26 , I-20133 Milan, Italy
- Istituto di Ricerca sulle Acque, IRSA-CNR, Via del Mulino 19 , I-20861 Brugherio (MB), Italy
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3
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Shogren EH, Anciães M, Barske J, Cestari C, DuVal EH, Gaiotti MG, Johnson EI, Kimball RT, Marini MA, Ryder TB, Scholer MN, Ungvári J, White SA, Boyle WA. Dancing drives evolution of sexual size dimorphism in manakins. Proc Biol Sci 2022; 289:20212540. [PMID: 35506220 PMCID: PMC9065976 DOI: 10.1098/rspb.2021.2540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Body size mediates life history, physiology and inter- and intra-specific interactions. Within species, sexes frequently differ in size, reflecting divergent selective pressures and/or constraints. Both sexual selection and differences in environmentally mediated reproductive constraints can drive sexual size dimorphism, but empirically testing causes of dimorphism is challenging. Manakins (Pipridae), a family of Neotropical birds comprising approximately 50 species, exhibit a broad range of size dimorphism from male- to female-biased and are distributed across gradients of precipitation and elevation. Males perform courtship displays ranging from simple hops to complex aerobatic manoeuvres. We tested associations between sexual size dimorphism and (a) agility and (b) environment, analysing morphological, behavioural and environmental data for 22 manakin species in a phylogenetic framework. Sexual dimorphism in mass was most strongly related to agility, with males being lighter than females in species performing more aerial display behaviours. However, wing and tarsus length dimorphism were more strongly associated with environmental variables, suggesting that different sources of selection act on different aspects of body size. These results highlight the strength of sexual selection in shaping morphology-even atypical patterns of dimorphism-while demonstrating the importance of constraints and ecological consequences of body size evolution.
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Affiliation(s)
- Elsie H. Shogren
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Marina Anciães
- Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas CEP 69.067-375, Brazil
| | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - César Cestari
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, CEP 38405-320, Brazil
| | - Emily H. DuVal
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Milene G. Gaiotti
- Departmento de Zoologia, Universidade de Brasília, Brasília 701910-900, Brazil
| | - Erik I. Johnson
- National Audubon Society, Baton Rouge, LA 70808, USA,Biological Dynamics of Forest Fragments Project, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas CPE 69.067-375, Brazil
| | - Rebecca T. Kimball
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Miguel A. Marini
- Departmento de Zoologia, Universidade de Brasília, Brasília 701910-900, Brazil
| | | | - Micah N. Scholer
- Biodiversity Research Centre and Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | | | - Stewart A. White
- School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - W. Alice Boyle
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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4
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Harvey C, Baliga VB, Wong JCM, Altshuler DL, Inman DJ. Birds can transition between stable and unstable states via wing morphing. Nature 2022; 603:648-653. [PMID: 35264798 PMCID: PMC8942853 DOI: 10.1038/s41586-022-04477-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 01/26/2022] [Indexed: 11/12/2022]
Abstract
Birds morph their wing shape to accomplish extraordinary manoeuvres1–4, which are governed by avian-specific equations of motion. Solving these equations requires information about a bird’s aerodynamic and inertial characteristics5. Avian flight research to date has focused on resolving aerodynamic features, whereas inertial properties including centre of gravity and moment of inertia are seldom addressed. Here we use an analytical method to determine the inertial characteristics of 22 species across the full range of elbow and wrist flexion and extension. We find that wing morphing allows birds to substantially change their roll and yaw inertia but has a minimal effect on the position of the centre of gravity. With the addition of inertial characteristics, we derived a novel metric of pitch agility and estimated the static pitch stability, revealing that the agility and static margin ranges are reduced as body mass increases. These results provide quantitative evidence that evolution selects for both stable and unstable flight, in contrast to the prevailing narrative that birds are evolving away from stability6. This comprehensive analysis of avian inertial characteristics provides the key features required to establish a theoretical model of avian manoeuvrability. Analysis of inertial characteristics across 22 bird species shows that evolution has selected for avian manoeuvrability using both stable and unstable flight dynamics.
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Affiliation(s)
- C Harvey
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - V B Baliga
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - J C M Wong
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - D L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - D J Inman
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI, USA
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5
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Kent E, Schwartz ALW, Perkins SE. Life in the fast lane: roadkill risk along an urban–rural gradient. JOURNAL OF URBAN ECOLOGY 2021. [DOI: 10.1093/jue/juaa039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Wildlife-vehicle collisions are a major cause of mortality in animal populations and can cause significant population-level effects. Urban areas are typically associated with higher road densities and unique wildlife communities in comparison to rural areas, and therefore have the potential to be associated with high numbers of collisions, and roadkill risk. Here, we use a citizen science database of wildlife roadkill and species distribution models to assess how roadkill risk (probability of roadkill observation per km2) varied along an urban–rural gradient for British wildlife. Roadkill risk was positively associated with road density, until around 5000 m/km2, a value representing villages or the outskirts of towns and cities. Beyond 5000 m/km2, risk remained high for some species (hedgehog, fox, pigeons and gulls) but reduced for other species (badger, rabbit, pheasant). Roadkill risk was a function of live species distribution for badger, hedgehog and rabbit, with significant overlap between spatial patterns of roadkill risk and the species’ live distribution. This was not the case for fox, pheasant, pigeons and gulls. Fox roadkill risk was underrepresented in rural areas, possibly due to low road density, while pheasant risk was overrepresented. For pigeons and gulls—well-known urban exploiters—roadkill risk was overrepresented in urban areas given their live distributions, possibly due to risks associated with foraging, particularly roadkill scavenging by gulls. Our results highlight the dangers of the UK’s dense road networks to wildlife, even to species considered adapted to urban environments and human disturbance.
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Affiliation(s)
- Eleri Kent
- Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
| | - Amy L W Schwartz
- Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
| | - Sarah E Perkins
- Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
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6
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de Barros FC, Grizante MB, Zampieri FAM, Kohlsdorf T. Peculiar relationships among morphology, burrowing performance and sand type in two fossorial microteiid lizards. ZOOLOGY 2020; 144:125880. [PMID: 33310388 DOI: 10.1016/j.zool.2020.125880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022]
Abstract
Associations among ecology, morphology and locomotor performance have been intensively investigated in several vertebrate lineages. Knowledge on how phenotypes evolve in natural environments likely benefits from identification of circumstances that might expand current ecomorphological equations. In this study, we used two species of Calyptommatus lizards from Brazilian Caatingas to evaluate if specific soil properties favor burrowing performance. As a derived prediction, we expected that functional associations would be easily detectable at the sand condition that favors low-resistance burrowing. We collected two endemic lizards and soil samples in their respective localities, obtained morphological data and recorded performance of both species in different sand types. As a result, the two species burrowed faster at the fine and homogeneous sand, the only condition where we detected functional associations between morphology and locomotion. In this sand type, lizards from both Calyptommatus species that have higher trunks and more concave heads were the ones that burrowed faster, and these phenotypic traits did not morphologically discriminate the two Calyptommatus populations studied. We discuss that integrative approaches comprising manipulation of environmental conditions clearly contribute to elucidate processes underlying phenotypic evolution in fossorial lineages.
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Affiliation(s)
- Fábio C de Barros
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil; Department of Ecology and Evolutionary Biology, ICAQF, Federal University of São Paulo, Rua Prof. Artur Riedel, 275, Diadema, SP, 09972-270, Brazil.
| | - Mariana B Grizante
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil; Instituto Dante Pazzanese de Cardiologia, Brazil
| | - Felipe A M Zampieri
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil
| | - Tiana Kohlsdorf
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil.
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7
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Dakin R, Segre PS, Altshuler DL. Individual variation and the biomechanics of maneuvering flight in hummingbirds. J Exp Biol 2020; 223:223/20/jeb161828. [DOI: 10.1242/jeb.161828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
An animal's maneuverability will determine the outcome of many of its most important interactions. A common approach to studying maneuverability is to force the animal to perform a specific maneuver or to try to elicit maximal performance. Recently, the availability of wider-field tracking technology has allowed for high-throughput measurements of voluntary behavior, an approach that produces large volumes of data. Here, we show how these data allow for measures of inter-individual variation that are necessary to evaluate how performance depends on other traits, both within and among species. We use simulated data to illustrate best practices when sampling a large number of voluntary maneuvers. Our results show how the sample average can be the best measure of inter-individual variation, whereas the sample maximum is neither repeatable nor a useful metric of the true variation among individuals. Our studies with flying hummingbirds reveal that their maneuvers fall into three major categories: simple translations, simple rotations and complex turns. Simple maneuvers are largely governed by distinct morphological and/or physiological traits. Complex turns involve both translations and rotations, and are more subject to inter-individual differences that are not explained by morphology. This three-part framework suggests that different wingbeat kinematics can be used to maximize specific aspects of maneuverability. Thus, a broad explanatory framework has emerged for interpreting hummingbird maneuverability. This framework is general enough to be applied to other types of locomotion, and informative enough to explain mechanisms of maneuverability that could be applied to both animals and bio-inspired robots.
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Affiliation(s)
- R. Dakin
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - P. S. Segre
- Department of Biology, Hopkins Marine Station, Stanford University, Stanford, CA 93950, USA
| | - D. L. Altshuler
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
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8
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Ecological drivers of global gradients in avian dispersal inferred from wing morphology. Nat Commun 2020; 11:2463. [PMID: 32424113 PMCID: PMC7235233 DOI: 10.1038/s41467-020-16313-6] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/16/2020] [Indexed: 12/24/2022] Open
Abstract
An organism’s ability to disperse influences many fundamental processes, from speciation and geographical range expansion to community assembly. However, the patterns and underlying drivers of variation in dispersal across species remain unclear, partly because standardised estimates of dispersal ability are rarely available. Here we present a global dataset of avian hand-wing index (HWI), an estimate of wing shape widely adopted as a proxy for dispersal ability in birds. We show that HWI is correlated with geography and ecology across 10,338 (>99%) species, increasing at higher latitudes and with migration, and decreasing with territoriality. After controlling for these effects, the strongest predictor of HWI is temperature variability (seasonality), with secondary effects of diet and habitat type. Finally, we also show that HWI is a strong predictor of geographical range size. Our analyses reveal a prominent latitudinal gradient in HWI shaped by a combination of environmental and behavioural factors, and also provide a global index of avian dispersal ability for use in community ecology, macroecology, and macroevolution. In birds, the hand-wing index is a morphological trait that can be used as a proxy for flight efficiency. Here the authors examine variation of hand-wing index in over 10,000 bird species, finding that it is higher in migratory and non-territorial species, and lower in the tropics.
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9
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Meresman Y, Husak JF, Ben-Shlomo R, Ribak G. Morphological diversification has led to inter-specific variation in elastic wing deformation during flight in scarab beetles. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200277. [PMID: 32431909 PMCID: PMC7211849 DOI: 10.1098/rsos.200277] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/09/2020] [Indexed: 05/07/2023]
Abstract
Insect wing shapes and the internal wing-vein arrangement are remarkably diverse. Although the wings lack intrinsic musculature to adjust shape actively, they elastically deform due to aerodynamic and inertial loads during flapping. In turn, the deformations alter the shape of the wing profile affecting the aerodynamic force. To determine how changes in wing-vein arrangement affect elastic wing deformation during free flight, we compared elastic wing deformations between free-flying rose chafers (Protaetia cuprea) and dung beetles (Scarabaeus puncticollis), complementing the comparison with wing static bending measurements. The broader relevance of the results to scarab beetle divergence was examined in a geometric morphometric (GM) analysis of wing-vein arrangement in 20 species differing in phylogeny and ecology. Despite rose chafers and dung beetles demonstrating similar flapping kinematics and wing size, the rose chafer wings undergo greater elastic deformation during flapping. GM analyses corrected for phylogenetic relatedness revealed that the two beetles represent extremes in wing morphology among the scarab subfamilies. Most of the differences occur at the distal leading edge and the proximal trailing edge of the wing, diversifying the flexibility of these regions, thereby changing the pattern of elastic wing deformation during flapping. Changes to local wing compliance seem to be associated with the diversification of scarab beetles to different food sources, perhaps as an adaptation to meet the demands of diverse flight styles.
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Affiliation(s)
- Y. Meresman
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - J. F. Husak
- Department of Biology, University of St. Thomas, Saint Paul, MN 55105, USA
| | - R. Ben-Shlomo
- Department of Biology and the Environment, University of Haifa-Oranim, Tivón, Israel
| | - G. Ribak
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- The Steinhardt Museum of Natural History, Israel National Center for Biodiversity Studies, Tel Aviv 6997801, Israel
- Author for correspondence: G. Ribak e-mail:
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10
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Parikh MB, Corcoran AJ, Hedrick TL. Competition and cooperation among chimney swifts at roost entry. BIOINSPIRATION & BIOMIMETICS 2019; 14:055005. [PMID: 31365904 DOI: 10.1088/1748-3190/ab3776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chimney swifts (Chaetura pelagica) are highly aerial, small, insectivorous birds well known for roosting en masse in chimneys during their autumn migration. These roosting events require hundreds to thousands of birds to enter a small opening (here 0.64 m2) within a short amount of time (15-30 min). Thus, these entry events pose a complex navigational and behavioral challenge as birds identify their entry route, cooperate with other birds present to form an entry flock, and compete with other birds at the time of chimney entry. We used six synchronized cameras to capture and reconstruct the 3D flight trajectories of swifts before and during chimney entry. Navigation into the chimney is consistent with use of a relative retinal expansion velocity cue, which results in an entry/non-entry decision point about 1.5 m above the chimney, or 0.4 s at typical entry speeds. Entries were highly clustered with 91 of 136 entries occurring within 1 s of another entry. We observed both synchronous (entry within 0.2 s) and sequential entry behavior (entry separated by ~0.4 s). Birds entering the chimney flew in close proximity to other birds (median minimum distance 0.51 m; 1.7 wingspans). In cases where two birds appeared to attempt a near-simultaneous entry, the bird either slightly to the rear or with a velocity vector bringing it closer to the current position of the other bird tended to make an avoidance maneuver and abandon its entry attempt. Overall, these results show how groups of animals execute complex landing and collision avoidance maneuvers in a natural setting without central control authority.
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Affiliation(s)
- Meera B Parikh
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
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11
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Rico-Guevara A, Sustaita D, Gussekloo S, Olsen A, Bright J, Corbin C, Dudley R. Feeding in Birds: Thriving in Terrestrial, Aquatic, and Aerial Niches. FEEDING IN VERTEBRATES 2019. [DOI: 10.1007/978-3-030-13739-7_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Henningsson P, Jakobsen L, Hedenström A. Aerodynamics of manoeuvring flight in brown long-eared bats ( Plecotus auritus). J R Soc Interface 2018; 15:rsif.2018.0441. [PMID: 30404906 DOI: 10.1098/rsif.2018.0441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
In this study, we explicitly examine the aerodynamics of manoeuvring flight in animals. We studied brown long-eared bats flying in a wind tunnel while performing basic sideways manoeuvres. We used particle image velocimetry in combination with high-speed filming to link aerodynamics and kinematics to understand the mechanistic basis of manoeuvres. We predicted that the bats would primarily use the downstroke to generate the asymmetries for the manoeuvre since it has been shown previously that the majority of forces are generated during this phase of the wingbeat. We found instead that the bats more often used the upstroke than they used the downstroke for this. We also found that the bats used both drag/thrust-based and lift-based asymmetries to perform the manoeuvre and that they even frequently switch between these within the course of a manoeuvre. We conclude that the bats used three main modes: lift asymmetries during downstroke, thrust/drag asymmetries during downstroke and thrust/drag asymmetries during upstroke. For future studies, we hypothesize that lift asymmetries are used for fast turns and thrust/drag for slow turns and that the choice between up- and downstroke depends on the timing of when the bat needs to generate asymmetries.
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Affiliation(s)
| | - Lasse Jakobsen
- Department of Biology, University of Southern Denmark, Odense, Denmark
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13
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Dakin R, Segre PS, Straw AD, Altshuler DL. Morphology, muscle capacity, skill, and maneuvering ability in hummingbirds. Science 2018; 359:653-657. [PMID: 29439237 DOI: 10.1126/science.aao7104] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/21/2017] [Indexed: 11/03/2022]
Abstract
How does agility evolve? This question is challenging because natural movement has many degrees of freedom and can be influenced by multiple traits. We used computer vision to record thousands of translations, rotations, and turns from more than 200 hummingbirds from 25 species, revealing that distinct performance metrics are correlated and that species diverge in their maneuvering style. Our analysis demonstrates that the enhanced maneuverability of larger species is explained by their proportionately greater muscle capacity and lower wing loading. Fast acceleration maneuvers evolve by recruiting changes in muscle capacity, whereas fast rotations and sharp turns evolve by recruiting changes in wing morphology. Both species and individuals use turns that play to their strengths. These results demonstrate how both skill and biomechanical traits shape maneuvering behavior.
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Affiliation(s)
- Roslyn Dakin
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada
| | - Paolo S Segre
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada
| | - Andrew D Straw
- Department of Animal Physiology, Neurobiology and Behavior, Faculty of Biology, University of Freiburg, Freiburg, D-79104, Germany
| | - Douglas L Altshuler
- Department of Zoology, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
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14
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de Margerie E, Pichot C, Benhamou S. Volume-concentrated searching by an aerial insectivore, the common swift, Apus apus. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2017.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Warrick DR, Hedrick TL, Biewener AA, Crandell KE, Tobalske BW. Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0391. [PMID: 27528781 DOI: 10.1098/rstb.2015.0391] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2016] [Indexed: 11/12/2022] Open
Abstract
While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows (Hirundo rustica) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3-2.0 m s(-1) across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02-6.1 m s(-1) While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
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Affiliation(s)
- Douglas R Warrick
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | - Tyson L Hedrick
- Department of Biology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Andrew A Biewener
- Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, Old Causeway Road, Bedford, MA 01730, USA
| | - Kristen E Crandell
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Bret W Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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16
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Tobalske BW. Evolution of avian flight: muscles and constraints on performance. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0383. [PMID: 27528773 DOI: 10.1098/rstb.2015.0383] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2016] [Indexed: 11/12/2022] Open
Abstract
Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
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Affiliation(s)
- Bret W Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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17
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Bryce CM, Wilmers CC, Williams TM. Energetics and evasion dynamics of large predators and prey: pumas vs. hounds. PeerJ 2017; 5:e3701. [PMID: 28828280 PMCID: PMC5563439 DOI: 10.7717/peerj.3701] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/26/2017] [Indexed: 01/17/2023] Open
Abstract
Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs (Canis lupus familiaris, 26 kg, n = 4-5 per chase) pursuing simultaneously instrumented solitary pumas (Puma concolor, 60 kg, n = 2). We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides) as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns) to increase their escape distance from the overall faster hounds (avg. 2.3× faster). These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76 vs. 1.29 kJ kg-1 min-1, respectively). On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted [Formula: see text] and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids.
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Affiliation(s)
- Caleb M. Bryce
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
- Botswana Predator Conservation Trust, Maun, Botswana
| | - Christopher C. Wilmers
- Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, CA, United States of America
| | - Terrie M. Williams
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
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18
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Saino N, Ambrosini R, Caprioli M, Liechti F, Romano A, Rubolini D, Scandolara C. Wing morphology, winter ecology, and fecundity selection: evidence for sex-dependence in barn swallows (Hirundo rustica). Oecologia 2017; 184:799-812. [PMID: 28741127 DOI: 10.1007/s00442-017-3918-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/14/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Nicola Saino
- Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133, Milan, Italy.
| | - Roberto Ambrosini
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Manuela Caprioli
- Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133, Milan, Italy
| | - Felix Liechti
- Swiss Ornithological Institute, Seerose 1, 6204, Sempach, Switzerland
| | - Andrea Romano
- Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133, Milan, Italy
| | - Diego Rubolini
- Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133, Milan, Italy
| | - Chiara Scandolara
- Department of Environmental Science and Policy, University of Milan, via Celoria 26, 20133, Milan, Italy
- Swiss Ornithological Institute, Seerose 1, 6204, Sempach, Switzerland
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19
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Chin DD, Matloff LY, Stowers AK, Tucci ER, Lentink D. Inspiration for wing design: how forelimb specialization enables active flight in modern vertebrates. J R Soc Interface 2017; 14:20170240. [PMID: 28592663 PMCID: PMC5493806 DOI: 10.1098/rsif.2017.0240] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/15/2017] [Indexed: 12/31/2022] Open
Abstract
Harnessing flight strategies refined by millions of years of evolution can help expedite the design of more efficient, manoeuvrable and robust flying robots. This review synthesizes recent advances and highlights remaining gaps in our understanding of how bird and bat wing adaptations enable effective flight. Included in this discussion is an evaluation of how current robotic analogues measure up to their biological sources of inspiration. Studies of vertebrate wings have revealed skeletal systems well suited for enduring the loads required during flight, but the mechanisms that drive coordinated motions between bones and connected integuments remain ill-described. Similarly, vertebrate flight muscles have adapted to sustain increased wing loading, but a lack of in vivo studies limits our understanding of specific muscular functions. Forelimb adaptations diverge at the integument level, but both bird feathers and bat membranes yield aerodynamic surfaces with a level of robustness unparalleled by engineered wings. These morphological adaptations enable a diverse range of kinematics tuned for different flight speeds and manoeuvres. By integrating vertebrate flight specializations-particularly those that enable greater robustness and adaptability-into the design and control of robotic wings, engineers can begin narrowing the wide margin that currently exists between flying robots and vertebrates. In turn, these robotic wings can help biologists create experiments that would be impossible in vivo.
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Affiliation(s)
- Diana D Chin
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Laura Y Matloff
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Amanda Kay Stowers
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Emily R Tucci
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
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20
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Zeng Y, Lam K, Chen Y, Gong M, Xu Z, Dudley R. Biomechanics of aerial righting in wingless nymphal stick insects. Interface Focus 2017; 7:20160075. [PMID: 28163868 DOI: 10.1098/rsfs.2016.0075] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Numerous wingless arthropods as well as diverse vertebrates are capable of mid-air righting. We studied the biomechanics of the aerial righting reflex in first-instar nymphs of the stick insect Extatosoma tiaratum. After being released upside-down, insects reoriented dorsoventrally and stabilized body posture via active modulation of limb positions and associated aerodynamic torques. We identified specific reflexes for bilaterally asymmetric leg displacements which elicit body rotation and subsequently stabilize mid-air posture. Coordinated appendicular movements thus improve torsional manoeuvrability in the absence of wings, as may have characterized the initial origins of controlled aerial behaviour in arthropods. Design of small aerial or multimodal robotic vehicles may similarly benefit from use of such strategies for flight control.
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Affiliation(s)
- Yu Zeng
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA; Department of Physics, University of California, Merced, CA, USA
| | - Kenrick Lam
- Department of Integrative Biology , University of California , Berkeley, CA 94720 , USA
| | - Yuexiang Chen
- Department of Integrative Biology , University of California , Berkeley, CA 94720 , USA
| | - Mengsha Gong
- Department of Integrative Biology , University of California , Berkeley, CA 94720 , USA
| | - Zheyuan Xu
- Department of Integrative Biology , University of California , Berkeley, CA 94720 , USA
| | - Robert Dudley
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA; Smithsonian Tropical Research Institute, Balboa, Republic of Panama
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21
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Huber GH, Turbek SP, Bostwick KS, Safran RJ. Comparative analysis reveals migratory swallows (Hirundinidae) have less pointed wings than residents. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12875] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gernot H. Huber
- Department of Ecology and Evolutionary Biology; Cornell University; Corson Hall Ithaca NY 14853 USA
| | - Sheela P. Turbek
- Department of Ecology and Evolutionary Biology; University of Colorado; Ramaley Hall Boulder CO 80309 USA
| | - Kimberly S. Bostwick
- Department of Ecology and Evolutionary Biology; Cornell University Museum of Vertebrates; Cornell University; Ithaca NY 14850 USA
| | - Rebecca J. Safran
- Department of Ecology and Evolutionary Biology; University of Colorado; Ramaley Hall Boulder CO 80309 USA
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22
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Song J, Tobalske BW, Powers DR, Hedrick TL, Luo H. Three-dimensional simulation for fast forward flight of a calliope hummingbird. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160230. [PMID: 27429779 PMCID: PMC4929914 DOI: 10.1098/rsos.160230] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/10/2016] [Indexed: 05/27/2023]
Abstract
We present a computational study of flapping-wing aerodynamics of a calliope hummingbird (Selasphorus calliope) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s(-1). The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome drag on the body, and such thrust production comes at price of negative lift induced during upstroke. This feature might be shared with bats, while being distinct from insects and other birds, including closely related swifts.
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Affiliation(s)
- Jialei Song
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Bret W. Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Donald R. Powers
- Department of Biology, George Fox University, Edwards-Holman Science Center, Newberg, OR 97132, USA
| | - Tyson L. Hedrick
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Haoxiang Luo
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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23
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Altshuler DL, Bahlman JW, Dakin R, Gaede AH, Goller B, Lentink D, Segre PS, Skandalis DA. The biophysics of bird flight: functional relationships integrate aerodynamics, morphology, kinematics, muscles, and sensors. CAN J ZOOL 2015. [DOI: 10.1139/cjz-2015-0103] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bird flight is a remarkable adaptation that has allowed the approximately 10 000 extant species to colonize all terrestrial habitats on earth including high elevations, polar regions, distant islands, arid deserts, and many others. Birds exhibit numerous physiological and biomechanical adaptations for flight. Although bird flight is often studied at the level of aerodynamics, morphology, wingbeat kinematics, muscle activity, or sensory guidance independently, in reality these systems are naturally integrated. There has been an abundance of new studies in these mechanistic aspects of avian biology but comparatively less recent work on the physiological ecology of avian flight. Here we review research at the interface of the systems used in flight control and discuss several common themes. Modulation of aerodynamic forces to respond to different challenges is driven by three primary mechanisms: wing velocity about the shoulder, shape within the wing, and angle of attack. For birds that flap, the distinction between velocity and shape modulation synthesizes diverse studies in morphology, wing motion, and motor control. Recently developed tools for studying bird flight are influencing multiple areas of investigation, and in particular the role of sensory systems in flight control. How sensory information is transformed into motor commands in the avian brain remains, however, a largely unexplored frontier.
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Affiliation(s)
- Douglas L. Altshuler
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Joseph W. Bahlman
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Roslyn Dakin
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Andrea H. Gaede
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Benjamin Goller
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Paolo S. Segre
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Dimitri A. Skandalis
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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24
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Segre PS, Dakin R, Zordan VB, Dickinson MH, Straw AD, Altshuler DL. Burst muscle performance predicts the speed, acceleration, and turning performance of Anna's hummingbirds. eLife 2015; 4:e11159. [PMID: 26583753 PMCID: PMC4737652 DOI: 10.7554/elife.11159] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/13/2015] [Indexed: 11/13/2022] Open
Abstract
Despite recent advances in the study of animal flight, the biomechanical determinants of maneuverability are poorly understood. It is thought that maneuverability may be influenced by intrinsic body mass and wing morphology, and by physiological muscle capacity, but this hypothesis has not yet been evaluated because it requires tracking a large number of free flight maneuvers from known individuals. We used an automated tracking system to record flight sequences from 20 Anna's hummingbirds flying solo and in competition in a large chamber. We found that burst muscle capacity predicted most performance metrics. Hummingbirds with higher burst capacity flew with faster velocities, accelerations, and rotations, and they used more demanding complex turns. In contrast, body mass did not predict variation in maneuvering performance, and wing morphology predicted only the use of arcing turns and high centripetal accelerations. Collectively, our results indicate that burst muscle capacity is a key predictor of maneuverability.
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Affiliation(s)
- Paolo S Segre
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Roslyn Dakin
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Victor B Zordan
- Department of Computer Science and Engineering, University of California, Riverside, Riverside, United States
| | - Michael H Dickinson
- Biology and Bioengineering, California Institute of Technology, Pasadena, United States
| | - Andrew D Straw
- Biology and Bioengineering, California Institute of Technology, Pasadena, United States.,Institute of Molecular Pathology, Vienna, Austria
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25
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Wilson RP, Griffiths IW, Mills MGL, Carbone C, Wilson JW, Scantlebury DM. Mass enhances speed but diminishes turn capacity in terrestrial pursuit predators. eLife 2015; 4. [PMID: 26252515 PMCID: PMC4542338 DOI: 10.7554/elife.06487] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 08/02/2015] [Indexed: 11/13/2022] Open
Abstract
The dynamics of predator-prey pursuit appears complex, making the development of a framework explaining predator and prey strategies problematic. We develop a model for terrestrial, cursorial predators to examine how animal mass modulates predator and prey trajectories and affects best strategies for both parties. We incorporated the maximum speed-mass relationship with an explanation of why larger animals should have greater turn radii; the forces needed to turn scale linearly with mass whereas the maximum forces an animal can exert scale to a 2/3 power law. This clarifies why in a meta-analysis, we found a preponderance of predator/prey mass ratios that minimized the turn radii of predators compared to their prey. It also explained why acceleration data from wild cheetahs pursuing different prey showed different cornering behaviour with prey type. The outcome of predator prey pursuits thus depends critically on mass effects and the ability of animals to time turns precisely. DOI:http://dx.doi.org/10.7554/eLife.06487.001 A pursuit between a predator and its prey involves complex strategies. Prey often make sudden sharp turns when running to evade a predator. Any predator that cannot turn quickly enough will have to run further to catch up with the prey again, thus potentially allowing the prey to pull away from the predator. The timing of these turns is crucial; if the prey turns when the predator is too far away, the predator can cut the corner off the turn and catch up with the prey more easily. The speed at which animals can turn depends on the forces involved in cornering, and larger animals need to produce greater forces for any given turn. However, larger animals can apply relatively less force than smaller animals for turns and so cannot turn as rapidly. The effect of the relationship between mass and turning ability on the strategies used during land-based pursuits had not been investigated. Wilson et al. have now created a mathematical model that considers how the mass of a predator and its prey influences the course and strategies used in a land-based pursuit. The model is based in part on a mathematical problem called the ‘homicidal chauffeur game’, where a car driver attempts to run over a pedestrian. Wilson et al.'s model predicts that chases between large predators and smaller prey should feature frequent sharp turns, as the prey try to exploit their superior turning ability. However, when the predators and prey are of similar size, the prey gain little or no advantage from executing high-speed turns. Indeed, as turning slows the prey down, turning may often be disadvantageous, and so fewer turns should be seen during a pursuit. The predictions of the model were compared with the pursuit strategies of wild cheetahs, which were studied using collars equipped with tags to measure acceleration as the predators chased prey of different sizes—from hares to large antelopes called gemsboks. The tracking data confirmed the predictions of the model; thereby revealing that body mass and the ability of animals to choose when best to turn strongly determine the outcome of predator-prey pursuits. DOI:http://dx.doi.org/10.7554/eLife.06487.002
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Affiliation(s)
- Rory P Wilson
- Swansea Lab for Animal Movement, Department of Biosciences, College of Science, Swansea University, Swansea, Wales
| | | | | | - Chris Carbone
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - John W Wilson
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - David M Scantlebury
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, United Kingdom
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26
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Bulbert MW, Page RA, Bernal XE. Danger comes from all fronts: predator-dependent escape tactics of túngara frogs. PLoS One 2015; 10:e0120546. [PMID: 25874798 PMCID: PMC4398479 DOI: 10.1371/journal.pone.0120546] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 01/23/2015] [Indexed: 11/22/2022] Open
Abstract
The escape response of an organism is generally its last line of defense against a predator. Because the effectiveness of an escape varies with the approach behaviour of the predator, it should be advantageous for prey to alter their escape trajectories depending on the mode of predator attack. To test this hypothesis we examined the escape responses of a single prey species, the ground-dwelling túngara frog (Engystomops pustulosus), to disparate predators approaching from different spatial planes: a terrestrial predator (snake) and an aerial predator (bat). Túngara frogs showed consistently distinct escape responses when attacked by terrestrial versus aerial predators. The frogs fled away from the snake models (Median: 131°). In stark contrast, the frogs moved toward the bat models (Median: 27°); effectively undercutting the bat’s flight path. Our results reveal that prey escape trajectories reflect the specificity of their predators’ attacks. This study emphasizes the flexibility of strategies performed by prey to outcompete predators with diverse modes of attack.
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Affiliation(s)
- Matthew W. Bulbert
- Behavioural Ecology Group, Department of Biology, Macquarie University, North Ryde, New South Wales, 2109, Australia
- Smithsonian Tropical Research Institute, Apartado 0843–03092, Balboa, Ancón, Panamá, República de Panamáa
- * E-mail:
| | - Rachel A. Page
- Smithsonian Tropical Research Institute, Apartado 0843–03092, Balboa, Ancón, Panamá, República de Panamáa
| | - Ximena E. Bernal
- Smithsonian Tropical Research Institute, Apartado 0843–03092, Balboa, Ancón, Panamá, República de Panamáa
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907–2054, United States of America
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27
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Hemelrijk CK, van Zuidam L, Hildenbrandt H. What underlies waves of agitation in starling flocks. Behav Ecol Sociobiol 2015; 69:755-764. [PMID: 26380537 PMCID: PMC4564680 DOI: 10.1007/s00265-015-1891-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 11/28/2022]
Abstract
Fast transfer of information in groups can have survival value. An example is the so-called wave of agitation observed in groups of animals of several taxa under attack. It has been shown to reduce predator success. It usually involves the repetition of a manoeuvre throughout the group, transmitting the information of the attack quickly, faster than the group moves itself. The specific manoeuvre underlying a wave is typically known, but not so in starlings (Sturnus vulgaris). Although waves of agitation in starling flocks have been suggested to reflect density waves, exact escape manoeuvres cannot be distinguished because flocks are spatially too far away. Therefore, waves may also reflect orientation waves (due to escape by rolling). In the present study, we investigate this issue in a computational model, StarDisplay. We use this model because its flocks have been shown to resemble starling flocks in many traits. In the model, we show that agitation waves result from changes in orientation rather than in density. They resemble empirical data both qualitatively in visual appearance and quantitatively in wave speed. In the model, local interactions with only two to seven closest neighbours suffice to generate empirical wave speed. Wave speed increases with the number of neighbours mimicked or repeated from and the distance to them. It decreases with reaction time and with time to identify the escape manoeuvre of others and is not affected by flock size. Our findings can be used as predictions for empirical studies.
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Affiliation(s)
- Charlotte K Hemelrijk
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Lars van Zuidam
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Hanno Hildenbrandt
- Behavioural Ecology and Self-organisation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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28
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Serrano FJ, Palmqvist P, Sanz JL. Multivariate analysis of neognath skeletal measurements: implications for body mass estimation in Mesozoic birds. Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12215] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Francisco José Serrano
- Área de Paleontología; Departamento de Ecología y Geología; Facultad de Ciencias; Universidad de Málaga; Campus Universitario de Teatinos s/n 29071 Málaga Spain
| | - Paul Palmqvist
- Área de Paleontología; Departamento de Ecología y Geología; Facultad de Ciencias; Universidad de Málaga; Campus Universitario de Teatinos s/n 29071 Málaga Spain
| | - José Luis Sanz
- Unidad de Paleontología; Departamento de Biología; C/Darwin 2; Universidad Autónoma de Madrid; Cantoblanco 28049 Madrid Spain
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Ros IG, Badger MA, Pierson AN, Bassman LC, Biewener AA. Pigeons produce aerodynamic torques through changes in wing trajectory during low speed aerial turns. ACTA ACUST UNITED AC 2014; 218:480-90. [PMID: 25452503 DOI: 10.1242/jeb.104141] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The complexity of low speed maneuvering flight is apparent from the combination of two critical aspects of this behavior: high power and precise control. To understand how such control is achieved, we examined the underlying kinematics and resulting aerodynamic mechanisms of low speed turning flight in the pigeon (Columba livia). Three birds were trained to perform 90 deg level turns in a stereotypical fashion and detailed three-dimensional (3D) kinematics were recorded at high speeds. Applying the angular momentum principle, we used mechanical modeling based on time-varying 3D inertia properties of individual sections of the pigeon's body to separate angular accelerations of the torso based on aerodynamics from those based on inertial effects. Directly measured angular accelerations of the torso were predicted by aerodynamic torques, justifying inferences of aerodynamic torque generation based on inside wing versus outside wing kinematics. Surprisingly, contralateral asymmetries in wing speed did not appear to underlie the 90 deg aerial turns, nor did contralateral differences in wing area, angle of attack, wingbeat amplitude or timing. Instead, torso angular accelerations into the turn were associated with the outside wing sweeping more anteriorly compared with a more laterally directed inside wing. In addition to moving through a relatively more retracted path, the inside wing was also more strongly pronated about its long axis compared with the outside wing, offsetting any difference in aerodynamic angle of attack that might arise from the observed asymmetry in wing trajectories. Therefore, to generate roll and pitch torques into the turn, pigeons simply reorient their wing trajectories toward the desired flight direction. As a result, by acting above the center of mass, the net aerodynamic force produced by the wings is directed inward, generating the necessary torques for turning.
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Affiliation(s)
- Ivo G Ros
- Harvard University, Department of Organismic and Evolutionary Biology, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - Marc A Badger
- University of California, Berkeley, Department of Integrative Biology, 3060 VLSB #3140, Berkeley, CA 94720, USA
| | - Alyssa N Pierson
- Harvey Mudd College, Department of Engineering, 301 Platt Boulevard, Claremont, CA 91711, USA
| | - Lori C Bassman
- Harvey Mudd College, Department of Engineering, 301 Platt Boulevard, Claremont, CA 91711, USA
| | - Andrew A Biewener
- Harvard University, Department of Organismic and Evolutionary Biology, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
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30
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Shelton RM, Jackson BE, Hedrick TL. The mechanics and behavior of cliff swallows during tandem flights. ACTA ACUST UNITED AC 2014; 217:2717-25. [PMID: 24855672 DOI: 10.1242/jeb.101329] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cliff swallows (Petrochelidon pyrrhonota) are highly maneuverable social birds that often forage and fly in large open spaces. Here we used multi-camera videography to measure the three-dimensional kinematics of their natural flight maneuvers in the field. Specifically, we collected data on tandem flights, defined as two birds maneuvering together. These data permit us to evaluate several hypotheses on the high-speed maneuvering flight performance of birds. We found that high-speed turns are roll-based, but that the magnitude of the centripetal force created in typical maneuvers varied only slightly with flight speed, typically reaching a peak of ~2 body weights. Turning maneuvers typically involved active flapping rather than gliding. In tandem flights the following bird copied the flight path and wingbeat frequency (~12.3 Hz) of the lead bird while maintaining position slightly above the leader. The lead bird turned in a direction away from the lateral position of the following bird 65% of the time on average. Tandem flights vary widely in instantaneous speed (1.0 to 15.6 m s(-1)) and duration (0.72 to 4.71 s), and no single tracking strategy appeared to explain the course taken by the following bird.
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Affiliation(s)
- Ryan M Shelton
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Brandon E Jackson
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Biological and Environmental Sciences, Longwood University, Farmville, VA 23909, USA
| | - Tyson L Hedrick
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Polidori C, Crottini A, Della Venezia L, Selfa J, Saino N, Rubolini D. Food load manipulation ability shapes flight morphology in females of central-place foraging Hymenoptera. Front Zool 2013; 10:36. [PMID: 23805850 PMCID: PMC3698194 DOI: 10.1186/1742-9994-10-36] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/20/2013] [Indexed: 11/18/2022] Open
Abstract
Background Ecological constraints related to foraging are expected to affect the evolution of morphological traits relevant to food capture, manipulation and transport. Females of central-place foraging Hymenoptera vary in their food load manipulation ability. Bees and social wasps modulate the amount of food taken per foraging trip (in terms of e.g. number of pollen grains or parts of prey), while solitary wasps carry exclusively entire prey items. We hypothesized that the foraging constraints acting on females of the latter species, imposed by the upper limit to the load size they are able to transport in flight, should promote the evolution of a greater load-lifting capacity and manoeuvrability, specifically in terms of greater flight muscle to body mass ratio and lower wing loading. Results Our comparative study of 28 species confirms that, accounting for shared ancestry, female flight muscle ratio was significantly higher and wing loading lower in species taking entire prey compared to those that are able to modulate load size. Body mass had no effect on flight muscle ratio, though it strongly and negatively co-varied with wing loading. Across species, flight muscle ratio and wing loading were negatively correlated, suggesting coevolution of these traits. Conclusions Natural selection has led to the coevolution of resource load manipulation ability and morphological traits affecting flying ability with additional loads in females of central-place foraging Hymenoptera. Release from load-carrying constraints related to foraging, which took place with the evolution of food load manipulation ability, has selected against the maintenance of a powerful flight apparatus. This could be the case since investment in flight muscles may have to be traded against other life-history traits, such as reproductive investment.
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Affiliation(s)
- Carlo Polidori
- Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), C/ José Gutiérrez Abascal 2, 28006 Madrid, Spain.
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Corbin CE, Lowenberger LK, Dorkoski RP. The skeleton flight apparatus of North American bluebirds (Sialia): phylogenetic thrushes or functional flycatchers? J Morphol 2013; 274:909-17. [PMID: 23576285 DOI: 10.1002/jmor.20147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/10/2013] [Accepted: 02/03/2013] [Indexed: 11/10/2022]
Abstract
To better understand ecological traits of organisms, one can study them from two, not necessarily mutually exclusive perspectives: how the traits evolved, and their current adaptive utility. In birds, foraging behavior and associated morphological traits generally are explained by a combination of adaptive and phylogenetic predictors. The avian skeleton and more specifically, the skeletal flight apparatus is under well-known functional and phylogenetic constraints. This is an interesting area to partition the relative contributions of adaptive correlated evolution and phylogenetic constraint to species clustering in morphological space. A prediction of convergent evolution is that nonphylogenetic morphological clustering is a characteristic of ecological similarity. We tested this using representatives of North American birds from two clades, one with a mixture of foraging modes (Turdid thrushes, solitaires, and bluebirds) and one with more canalized foraging behaviors (Tyrannid flycatchers). Nine characters on the skeletal flight apparatus from 19 species were used to characterize the morphological space and test for ecomorphological clustering. When body size and phylogeny are considered, the three bluebird species and Townsend's solitaire cluster with the ecologically similar flycatchers rather than with their phylogenetic close relatives. Furthermore, sit-and-wait foragers tend to exhibit relatively long distal elements and a long keel while active ground foragers have deeper keels and a longer humerus. Distal elements, expected to be relatively shorter and more bowed in the flycatchers and bluebirds, were actually longer and narrower. A reduction of distal element mass may be more important for facilitating maneuverability than surface area for insertion of wing-rotational musculature.
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Affiliation(s)
- Clay E Corbin
- Department of Biological and Allied Health Sciences, Bloomsburg University, Bloomsburg, Pennsylvania 17815, USA.
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Timing of arrival from spring migration is associated with flight performance in the migratory barn swallow. Behav Ecol Sociobiol 2012; 67:91-100. [PMID: 23293424 PMCID: PMC3536968 DOI: 10.1007/s00265-012-1429-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/23/2012] [Accepted: 10/03/2012] [Indexed: 11/25/2022]
Abstract
Timing of arrival at the breeding grounds by migratory birds affects their mating success and access to superior resources, thus being a major factor associated with fitness. Much empirical work has been devoted to investigate the condition dependence of arrival sequence of migrants and characteristics of individuals that influence arrival time from migration. Surprisingly, there are no studies examining the relationship between flight performance of individual birds and their arrival time. I investigated the relative importance of direct effects of short-term flight performance, age, body condition and the degree of sexual ornamentation (tail length) on timing of spring arrival in the barn swallow (Hirundo rustica), a long-distance trans-equatorial passerine migrant. I evaluated short-term flight performance (a composite variable comprising flight manoeuvrability, velocity and acceleration) in a standardised manner using flight tunnels. Short-term flight performance was a significant and important predictor of spring arrival date. Furthermore, locomotion predicted arrival date of individual birds independently of morphological variables—the degree of sexual ornamentation (the length of the tail) and wing aspect ratio and body condition. I discuss the possible role short-term flight performance may have in determining migratory performance. This is the first time flight performance has been shown to be associated with timing of arrival from migration in a migratory bird.
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Combes SA, Rundle DE, Iwasaki JM, Crall JD. Linking biomechanics and ecology through predator–prey interactions: flight performance of dragonflies and their prey. J Exp Biol 2012; 215:903-13. [PMID: 22357584 DOI: 10.1242/jeb.059394] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Aerial predation is a highly complex, three-dimensional flight behavior that affects the individual fitness and population dynamics of both predator and prey. Most studies of predation adopt either an ecological approach in which capture or survival rates are quantified, or a biomechanical approach in which the physical interaction is studied in detail. In the present study, we show that combining these two approaches provides insight into the interaction between hunting dragonflies (Libellula cyanea) and their prey (Drosophila melanogaster) that neither type of study can provide on its own. We performed >2500 predation trials on nine dragonflies housed in an outdoor artificial habitat to identify sources of variability in capture success, and analyzed simultaneous predator–prey flight kinematics from 50 high-speed videos. The ecological approach revealed that capture success is affected by light intensity in some individuals but that prey density explains most of the variability in success rate. The biomechanical approach revealed that fruit flies rarely respond to approaching dragonflies with evasive maneuvers, and are rarely successful when they do. However, flies perform random turns during flight, whose characteristics differ between individuals, and these routine, erratic turns are responsible for more failed predation attempts than evasive maneuvers. By combining the two approaches, we were able to determine that the flies pursued by dragonflies when prey density is low fly more erratically, and that dragonflies are less successful at capturing them. This highlights the importance of considering the behavior of both participants, as well as their biomechanics and ecology, in developing a more integrative understanding of organismal interactions.
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Affiliation(s)
- S. A. Combes
- Harvard University, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - D. E. Rundle
- Harvard University, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - J. M. Iwasaki
- Harvard University, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
| | - J. D. Crall
- Harvard University, Concord Field Station, 100 Old Causeway Road, Bedford, MA 01730, USA
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36
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van den Hout PJ, Mathot KJ, Maas LR, Piersma T. Predator escape tactics in birds: linking ecology and aerodynamics. Behav Ecol 2009. [DOI: 10.1093/beheco/arp146] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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BLEIWEISS ROBERT. The tail end of hummingbird evolution: parallel flight system development in living and ancient birds. Biol J Linn Soc Lond 2009. [DOI: 10.1111/j.1095-8312.2009.01240.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Clark CJ. Courtship dives of Anna's hummingbird offer insights into flight performance limits. Proc Biol Sci 2009; 276:3047-52. [PMID: 19515669 DOI: 10.1098/rspb.2009.0508] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behavioural displays are a common feature of animal courtship. Just as female preferences can generate exaggerated male ornaments, female preferences for dynamic behaviours may cause males to perform courtship displays near intrinsic performance limits. I provide an example of an extreme display, the courtship dive of Anna's hummingbird (Calypte anna). Diving male Anna's hummingbirds were filmed with a combination of high-speed and conventional video cameras. After powering the initial stage of the dive by flapping, males folded their wings by their sides, at which point they reached an average maximum velocity of 385 body lengths s(-1) (27.3 m s(-1)). This is the highest known length-specific velocity attained by any vertebrate. This velocity suggests their body drag coefficient is less than 0.3. They then spread their wings to pull up, and experienced centripetal accelerations nearly nine times greater than gravitational acceleration. This acceleration is the highest reported for any vertebrate undergoing a voluntary aerial manoeuvre, except jet fighter pilots. Stereotyped courtship behaviours offer several advantages for the study of extreme locomotor performance, and can be assessed in a natural context.
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39
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Iriarte-Díaz J, Swartz SM. Kinematics of slow turn maneuvering in the fruit batCynopterus brachyotis. J Exp Biol 2008; 211:3478-89. [DOI: 10.1242/jeb.017590] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYManeuvering abilities have long been considered key factors that influence habitat selection and foraging strategies in bats. To date, however, very little experimental work has been carried out to understand the mechanisms that bats use to perform maneuvers. In the present study, we examined the kinematics of slow-speed turning flight in the lesser short-nosed fruit bat, Cynopterus brachyotis, to understand the basic mechanics employed to perform maneuvers and to compare them with previous findings in bats and other flying organisms. Four individuals were trained to fly in L-shaped flight enclosure that required them to make a 90 deg. turn midway through each flight. Flights were recorded with three low-light, high-speed videocameras,allowing the three-dimensional reconstruction of the body and wing kinematics. For any flying organisms, turning requires changes of the direction of travel and the reorientation of the body around the center of mass to maintain the alignment with the flight direction. In C. brachyotis, changes in body orientation (i.e. heading) took place during upstroke and preceded the changes in flight direction, which were restricted to the downstroke portion of the wingbeat cycle. Mean change in flight direction was significantly correlated to the mean heading angular velocity at the beginning of the downstroke and to the mean bank angle during downstroke, although only heading velocity was significant when both variables were considered. Body reorientation prior to changes in direction might be a mechanism to maintain the head and body aligned with the direction of travel and, thus, maximizing spatial accuracy in three-dimensionally complex environments.
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Affiliation(s)
- José Iriarte-Díaz
- Department of Ecology and Evolutionary Biology, Brown University, Providence,RI 02912, USA
| | - Sharon M. Swartz
- Department of Ecology and Evolutionary Biology, Brown University, Providence,RI 02912, USA
- Division of Engineering, Brown University, Providence, RI 02912, USA
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Abstract
SUMMARYPower output is a unifying theme for bird flight and considerable progress has been accomplished recently in measuring muscular, metabolic and aerodynamic power in birds. The primary flight muscles of birds, the pectoralis and supracoracoideus, are designed for work and power output, with large stress (force per unit cross-sectional area) and strain (relative length change) per contraction. U-shaped curves describe how mechanical power output varies with flight speed, but the specific shapes and characteristic speeds of these curves differ according to morphology and flight style. New measures of induced, profile and parasite power should help to update existing mathematical models of flight. In turn, these improved models may serve to test behavioral and ecological processes. Unlike terrestrial locomotion that is generally characterized by discrete gaits, changes in wing kinematics and aerodynamics across flight speeds are gradual. Take-off flight performance scales with body size, but fully revealing the mechanisms responsible for this pattern awaits new study. Intermittent flight appears to reduce the power cost for flight, as some species flap–glide at slow speeds and flap–bound at fast speeds. It is vital to test the metabolic costs of intermittent flight to understand why some birds use intermittent bounds during slow flight. Maneuvering and stability are critical for flying birds,and design for maneuvering may impinge upon other aspects of flight performance. The tail contributes to lift and drag; it is also integral to maneuvering and stability. Recent studies have revealed that maneuvers are typically initiated during downstroke and involve bilateral asymmetry of force production in the pectoralis. Future study of maneuvering and stability should measure inertial and aerodynamic forces. It is critical for continued progress into the biomechanics of bird flight that experimental designs are developed in an ecological and evolutionary context.
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Affiliation(s)
- Bret W Tobalske
- Department of Biology, University of Portland, 5000 North Willamette Boulevard, Portland, OR 97203, USA.
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41
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Schmidt-Wellenburg CA, Biebach H, Daan S, Visser GH. Energy expenditure and wing beat frequency in relation to body mass in free flying Barn Swallows (Hirundo rustica). J Comp Physiol B 2006; 177:327-37. [PMID: 17171355 DOI: 10.1007/s00360-006-0132-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 11/03/2006] [Accepted: 11/11/2006] [Indexed: 11/30/2022]
Abstract
Many bird species steeply increase their body mass prior to migration. These fuel stores are necessary for long flights and to overcome ecological barriers. The elevated body mass is generally thought to cause higher flight costs. The relationship between mass and costs has been investigated mostly by interspecific comparison and by aerodynamic modelling. Here, we directly measured the energy expenditure of Barn Swallows (Hirundo rustica) flying unrestrained and repeatedly for several hours in a wind tunnel with natural variations in body mass. Energy expenditure during flight (e (f), in W) was found to increase with body mass (m, in g) following the equation e (f) = 0.38 x m (0.58). The scaling exponent (0.58) is smaller than assumed in aerodynamic calculations and than observed in most interspecific allometric comparisons. Wing beat frequency (WBF, in Hz) also scales with body mass (WBF = 2.4 x m (0.38)), but at a smaller exponent. Hence there is no linear relationship between e (f) and WBF. We propose that spontaneous changes in body mass during endurance flights are accompanied by physiological changes (such as enhanced oxygen and nutrient supply of the muscles) that are not taken into consideration in standard aerodynamic calculations, and also do not appear in interspecific comparison.
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Affiliation(s)
- Carola A Schmidt-Wellenburg
- Department of Biological Rhythms and Behaviour, Max Planck Institute for Ornithology, Von-der-Tann-Str. 7, 82346 Andechs, Germany.
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Bowlin MS, Winkler DW. Natural Variation in Flight Performance is Related to Timing of Breeding in Tree Swallows (Tachycineta Bicolor) in New York. ACTA ACUST UNITED AC 2004. [DOI: 10.1093/auk/121.2.345] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIn many avian species, including Tree Swallows (Tachycineta bicolor), females that lay eggs earlier in the season have higher fitness. It has been hypothesized that nonheritable variation in individual quality could explain how variation in laying date persists in the face of this apparently directional selection. Previous experimental work on Tree Swallows has suggested that natural variation in flight ability enables early-laying females to attain feeding rates high enough to support egg production on earlier, sparser food than later-laying females. We tested that hypothesis with standardized flights through a 9.75-m flight-performance test tunnel. One group of female swallows was tested at the height of the breeding season on 28 May regardless of their nesting phenology; another group was tested on the 11th day of incubation. Average acceleration in the tunnel was negatively correlated with clutch initiation date for the females tested on 28 May. Daily variation in ambient environmental conditions had strong effects on swallow flight performance in the tunnel, and no relationship was observed in the day-11 birds. Because natural variation in foraging performance is correlated with variation in female Tree Swallows' clutch initiation dates, flight ability appears to be a key element of individual quality in this species.
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Affiliation(s)
- Melissa S. Bowlin
- Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14850, USA
| | - David W. Winkler
- Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14850, USA
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43
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Barbosa A, Merino S, Lope F, Møller AP. Effects of Feather Lice on Flight Behavior of Male Barn Swallows (Hirundo Rustica). ACTA ACUST UNITED AC 2002. [DOI: 10.1093/auk/119.1.213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Parasites may affect host behavior in a number of ways, including their locomotory performance. We investigated whether the number of holes produced by the feather louse (Myrsidea rustica) affected flight behavior in adult male Barn Swallows (Hirundo rustica) by video-taping flight performance of individuals during escape and level flight. Percentage of time spent flapping during foraging flight was positively related to number of holes, but not to other flight parameters such as wingbeat frequency. These results suggest indirect effects of feather lice on host performance that must be considered together with effects of thermoregulation and feather breakage. This is the first report of an effect of parasite load on flight behavior.
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Affiliation(s)
- A. Barbosa
- Estación Experimental de Zonas Áridas, CSIC, C/General Segura, 1, E-04001 Almeria, Spain
| | - S. Merino
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, C/José Gutiérrez Abascal, 2, E-28006 Madrid, Spain
| | - Fde Lope
- Departamento de Biología Animal, Facultad de Biología, Universidad de Extremadura, Avda. de Elvas s/n, E-06071 Badajoz, Spain
| | - A. P. Møller
- Laboratoire d'Ecologie, CNRS-URA 258, Université Pierre et Marie Curie, Bat A 7e etage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France
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Bruderer L, Liechti F, Bilo D. Flexibility in flight behaviour of barn swallows (Hirundo rustica) and house martins (Delichon urbica) tested in a wind tunnel. J Exp Biol 2001; 204:1473-84. [PMID: 11273808 DOI: 10.1242/jeb.204.8.1473] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The flight behaviour of barn swallows (Hirundo rustica) and house martins (Delichon urbica) was tested in a wind tunnel at 15 combinations of flight angles and speeds. In contrast to that of most other small passerines, the intermittent flight of hirundines rarely consists of regular patterns of flapping and rest phases. To vary mechanical power output, both species used intermittent flight, controlling the number of single, pulse-like wingbeats per unit time. House martins in descent tended to concentrate their wingbeats into bursts and performed true gliding flight during rest phases. Barn swallows mainly performed partial bounds during brief interruptions of upstrokes, which they progressively prolonged with decreasing flight angle. Thus, identification of distinct flapping phases to calculate wingbeat frequencies was not feasible. Instead, an effective wingbeat frequency for flight intervals of 20 s, including partial bounds, was introduced. The effective wingbeat frequencies of house martins (N=3) ranged from 2 to 10.5 s(−)(1), those of barn swallows (N=4) from 2.5 to 8.5 s(−)(1). In both hirundine species, effective wingbeat frequency was found to decrease almost linearly with decreasing flight angle. With changes in air speed, wingbeat frequency varied according to a U-shaped curve, suggesting a minimum power speed of roughly 9 m s(−)(1). The duration of the down- and upstrokes varied systematically depending on flight angle and air speed.
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Affiliation(s)
- L Bruderer
- Swiss Ornithological Institute, CH-6204 Sempach, Switzerland
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Abstract
While experimental analyses of steady rectilinear locomotion in fishes are common, unsteady movement involving time-dependent variation in heading, speed and acceleration probably accounts for the greatest portion of the locomotor time budget. Turning maneuvers, in particular, are key elements of the unsteady locomotor repertoire of fishes and, by many species, are accomplished by generating asymmetrical forces with the pectoral fins. The development of such left-right asymmetries in force production is a critical and as yet unstudied aspect of aquatic locomotor dynamics. In this paper, we measure the fluid forces exerted by the left and right pectoral fins of bluegill sunfish (Lepomis macrochirus) during turning using digital particle image velocimetry (DPIV). DPIV allowed quantification of water velocity fields, and hence momentum, in the wake of the pectoral fins as sunfish executed turns; forces exerted during turning were compared with those generated by the immediately preceding fin beats during steady swimming. Sunfish generate the forces required for turning by modulating two variables: wake momentum and pectoral fin stroke timing. Fins on opposite sides of the fish play functionally distinct roles during turning maneuvers. The fin nearer the stimulus inducing the turn (i.e. the strong side fin) generates a laterally oriented vortex ring with a strong central jet whose associated lateral force is four times greater than that produced during steady swimming. Little posterior (thrust) force is generated by the strong-side fin, and this fin therefore acts to rotate the body away from the source of the stimulus. The contralateral (weak-side) fin generates a posteriorly oriented vortex ring with a thrust force nine times that produced by the fin during steady swimming. Minimal lateral force is exerted by the weak-side fin, and this fin therefore acts primarily to translate the body linearly away from the stimulus. Turning with the paired fins is not simply steady swimming performed unilaterally. Instead, turning involves asymmetrical fin movements and fluid forces that are distinct in both direction and magnitude from those used to swim forward at constant speed. These data reflect the plasticity of the teleost pectoral fin in performing a wide range of steady and unsteady locomotor tasks.
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Affiliation(s)
- E G Drucker
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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Tobalske BW. Biomechanics and physiology of gait selection in flying birds. Physiol Biochem Zool 2000; 73:736-50. [PMID: 11121347 DOI: 10.1086/318107] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2000] [Indexed: 11/03/2022]
Abstract
Two wing-beat gaits, distinguished by the presence or absence of lift production during the upstroke, are currently used to describe avian flight. Vortex-visualization studies indicate that lift is produced only during the downstroke in the vortex-ring gait and that lift is produced continuously in the continuous-vortex gait. Tip-reversal and feathered upstrokes represent different forms of vortex-ring gait distinguished by wing kinematics. Useful aerodynamic forces may be produced during tip-reversal upstroke in slow flight and during a feathered upstroke in fast flight, but it is probable that downstroke forces are much greater in magnitude. Uncertainty about the function of these types of upstroke may be resolved when more data are available on wake structure in different flight speeds and modes. Inferring from wing kinematics and available data on wake structure, birds with long wings or wings of high aspect ratio use a vortex-ring gait with tip-reversal upstroke at slow speeds, a vortex-ring gait with a feathered upstroke at intermediate speeds, and a continuous-vortex gait at fast speeds. Birds with short wings or wings of low aspect ratio use a vortex-ring gait with a feathered upstroke at all speeds. Regardless of wing shape, species tend to use a vortex-ring gait for acceleration and a continuous-vortex gait for deceleration. Some correlations may exist between gait selection and the function of the muscular and respiratory system. However, overall variation in wing kinematics, muscle activity, and respiratory activity is continuous rather than categorical. To further our understanding of gait selection in flying birds, it is important to test whether upstroke function varies in a similar manner. Transitions between lifting and nonlifting upstrokes may be more subtle and gradual than implied by a binomial scheme of classification.
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Affiliation(s)
- B W Tobalske
- Department of Biology, University of Portland, 5000 North Willamette Boulevard, Portland, OR 97203, USA.
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Tobalske BW, Dial KP. Effects of body size on take-off flight performance in the Phasianidae (Aves). J Exp Biol 2000; 203:3319-32. [PMID: 11023852 DOI: 10.1242/jeb.203.21.3319] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To evaluate the mechanisms responsible for relationships between body mass and maximum take-off performance in birds, we studied four species in the Phasianidae: northern bobwhite (Colinus virginianus), chukar (Alectoris chukar), ring-necked pheasant (Phasianus colchicus) and wild turkey (Meleagris gallopavo). These species vary in body mass from 0.2 to 5.3 kg, and they use flight almost solely to escape predators. During take-off, all the species used a similar wingbeat style that appeared to be a vortex-ring gait with a tip reversal during the upstroke. The tip reversal is unusual for birds with rounded wings; it may offer an aerodynamic advantage during rapid acceleration. Flight anatomy generally scaled geometrically, except for average wing chord and wing area, which increased more than expected as body mass (m) increased. Pectoralis strain varied from 19.1 to 35.2 % and scaled in proportion to m(0.23). This positive scaling is not consistent with the widely held assumption that muscle strain is independent of body mass among geometrically similar species. The anatomy of the species precluded measurements of in vivo pectoralis force using the strain-gauge technique that has been employed successfully in other bird species, so we could not directly test in vivo pectoralis force-velocity relationships. However, whole-body kinematics revealed that take-off power (P(ta)), the excess power available for climbing and accelerating in flight, scaled in proportion to m(0.75) and that pectoralis mass-specific P(ta) decreased in proportion to m(−)(0.26) and was directly proportional to wingbeat frequency. These trends suggest that mass-specific pectoralis work did not vary with body mass and that pectoralis stress and strain were inversely proportional, as expected from classical force-velocity models for skeletal muscle. Our observations of P(ta) were consistent with evidence from other species engaged in escape flight and, therefore, appear to contradict evidence from studies of take-off or hovering with an added payload.
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Affiliation(s)
- B W Tobalske
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
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Tobalske BW, Peacock WL, Dial KP. Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds. J Exp Biol 1999; 202 (Pt 13):1725-39. [PMID: 10359676 DOI: 10.1242/jeb.202.13.1725] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It has been proposed elsewhere that flap-bounding, an intermittent flight style consisting of flapping phases interspersed with flexed-wing bounds, should offer no savings in average mechanical power relative to continuous flapping unless a bird flies 1.2 times faster than its maximum range speed (Vmr). Why do some species use intermittent bounds at speeds slower than 1.2Vmr? The ‘fixed-gear hypothesis’ suggests that flap-bounding is used to vary mean power output in small birds that are otherwise constrained by muscle physiology and wing anatomy to use a fixed muscle shortening velocity and pattern of wing motion at all flight speeds; the ‘body-lift hypothesis’ suggests that some weight support during bounds could make flap-bounding flight aerodynamically advantageous in comparison with continuous flapping over most forward flight speeds. To test these predictions, we studied high-speed film recordings (300 Hz) of wing and body motion in zebra finches (Taenopygia guttata, mean mass 13.2 g, N=4) taken as the birds flew in a variable-speed wind tunnel (0–14 m s-1). The zebra finches used flap-bounding flight at all speeds, so their flight style was unique compared with that of birds that facultatively shift from continuous flapping or flap-gliding at slow speeds to flap-bounding at fast speeds. There was a significant effect of flight speed on all measured aspects of wing motion except percentage of the wingbeat spent in downstroke. Changes in angular velocity of the wing indicated that contractile velocity in the pectoralis muscle changed with flight speed, which is not consistent with the fixed-gear hypothesis. Although variation in stroke-plane angle relative to the body, pronation angle of the wing and wing span at mid-upstroke showed that the zebra finch changed within-wingbeat geometries according to speed, a vortex-ring gait with a feathered upstroke appeared to be the only gait used during flapping. In contrast, two small species that use continuous flapping during slow flight (0–4 m s-1) either change wingbeat gait according to flight speed or exhibit more variation in stroke-plane and pronation angles relative to the body. Differences in kinematics among species appear to be related to wing design (aspect ratio, skeletal proportions) rather than to pectoralis muscle fiber composition, indicating that the fixed-gear hypothesis should perhaps be modified to exclude muscle physiology and to emphasize constraints due to wing anatomy. Body lift was produced during bounds at speeds from 4 to 14 m s-1. Maximum body lift was 0.0206 N (15.9 % of body weight) at 10 m s-1; body lift:drag ratio declined with increasing air speed. The aerodynamic function of bounds differed with increasing speed from an emphasis on lift production (4–10 m s-1) to an emphasis on drag reduction with a slight loss in lift (12 and 14 m s-1). From a mathematical model of aerodynamic costs, it appeared that flap-bounding offered the zebra finch an aerodynamic advantage relative to continuous flapping at moderate and fast flight speeds (6–14 m s-1), with body lift augmenting any savings offered solely by flap-bounding at speeds faster than 7.1 m s-1. The percentage of time spent flapping during an intermittent flight cycle decreased with increasing speed, so the mechanical cost of transport was likely to be lowest at faster flight speeds (10–14 m s-1).
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Affiliation(s)
- BW Tobalske
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
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