1
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Monier SA. Social interactions and information use by foraging seabirds. Biol Rev Camb Philos Soc 2024. [PMID: 38693884 DOI: 10.1111/brv.13089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 05/03/2024]
Abstract
What do seabirds perceive about the world? How do they do so? And how do they use the information available to them to make foraging decisions? Social cues provide seabirds with information about the location of prey. This can, of course, be passive and not involve higher-order cognitive processes (e.g. simple conspecific or heterospecific attraction). However, seabirds display many behaviours that promote learning and the transmission of information between individuals: the vast majority of seabirds are colonial living, have an extended juvenile phase that affords them time to learn, routinely form intra- and interspecific associations, and can flexibly deploy a combination of foraging tactics. It is worth evaluating their foraging interactions in light of this. This review describes how seabirds use social information both at the colony and at sea to forage, and discusses the variation that exists both across species and amongst individuals. It is clear that social interactions are a critical and beneficial component of seabird foraging, with most of the variation concerning the way and extent to which social information is used, rather than whether it is used. While it may seem counterintuitive that large groups of potential competitors congregating at a patch can result in foraging gains, such aggregations can alter species dynamics in ways that promote coexistence. This review explores how competitive interference at a patch can be mitigated by behavioural modifications and niche segregation. Utilising others for foraging success (e.g. via social cues and facilitation at a patch) is likely to make population declines particularly damaging to seabirds if the quantity or quality of their social foraging interactions is reduced. Environmental changes have the potential to disrupt their social networks and thus, how these species obtain food and transfer information.
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Affiliation(s)
- Samantha Anne Monier
- Biology Department, The Graduate Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA
- Biology Department, College of Staten Island, 2800 Victory Blvd., Staten Island, NY, 10314, USA
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2
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Emmerson L, Southwell C. Environment-triggered demographic changes cascade and compound to propel a dramatic decline of an Antarctic seabird metapopulation. GLOBAL CHANGE BIOLOGY 2022; 28:7234-7249. [PMID: 36214124 DOI: 10.1111/gcb.16437] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 08/07/2022] [Indexed: 06/16/2023]
Abstract
While seabirds are well-known for making a living under some of the harshest conditions on the planet, their capacity to buffer against unfavourable conditions can be stretched in response to ecosystem change. During population increases, overlap between conspecifics can limit population growth through competition for breeding or feeding resources. What is less well understood is the role that intrinsic processes play during periods of population decline or under a changing environment. We interrogate key demographic parameters and their biophysical drivers to understand the role of intrinsic and extrinsic drivers during a recent near halving of a large Adélie penguin (Pygoscelis adeliae) metapopulation. The loss of 154,000 breeding birds along the 100-km East Antarctic coastline centred around 63°E over the last decade diverges from a sustained increase over preceding decades and is contrary to recent models that predict a continued increase. The decline was initially triggered by changed environmental conditions: more extensive near-shore sea ice caused a reduction in breeding success. The evidence suggests this decline was exacerbated by feedback processes driving an inverse density-dependent decrease in fledgling survival in response to smaller cohort size. It appears that the old adage of safety in numbers may shape the fledgling penguins' chances of survival and, if compromised over multiple years, could exacerbate difficulties during population decline or if feedback processes arise. The likely interplay between demographic parameters meant that conditions were more unfavourable and negative effects more rapid than would be expected if demographic processes acted in isolation or independently. Failure to capture both intrinsic and extrinsic drivers in predictive population models may mean that the real impacts of climate change on species' populations are more severe than projections would lead us to believe. These results improve our understanding of population regulation during periods of rapid decline for long-lived marine species.
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Affiliation(s)
- Louise Emmerson
- Department of Climate Change, Energy, the Environment and Water, Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Colin Southwell
- Department of Climate Change, Energy, the Environment and Water, Australian Antarctic Division, Kingston, Tasmania, Australia
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3
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McGrew KA, Crowell SE, Fiely JL, Berlin AM, Olsen GH, James J, Hopkins H, Williams CK. Underwater hearing in sea ducks with applications for reducing gillnet bycatch through acoustic deterrence. J Exp Biol 2022; 225:jeb243953. [PMID: 36305674 PMCID: PMC10658911 DOI: 10.1242/jeb.243953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
As diving foragers, sea ducks are vulnerable to underwater anthropogenic activity, including ships, underwater construction, seismic surveys and gillnet fisheries. Bycatch in gillnets is a contributing source of mortality for sea ducks, killing hundreds of thousands of individuals annually. We researched underwater hearing in sea duck species to increase knowledge of underwater avian acoustic sensitivity and to assist with possible development of gillnet bycatch mitigation strategies that include auditory deterrent devices. We used both psychoacoustic and electrophysiological techniques to investigate underwater duck hearing in several species including the long-tailed duck (Clangula hyemalis), surf scoter (Melanitta perspicillata) and common eider (Somateria mollissima). Psychoacoustic results demonstrated that all species tested share a common range of maximum auditory sensitivity of 1.0-3.0 kHz, with the long-tailed ducks and common eiders at the high end of that range (2.96 kHz), and surf scoters at the low end (1.0 kHz). In addition, our electrophysiological results from 4 surf scoters and 2 long-tailed ducks, while only tested at 0.5, 1 and 2 kHz, generally agree with the audiogram shape from our psychoacoustic testing. The results from this study are applicable to the development of effective acoustic deterrent devices or pingers in the 2-3 kHz range to deter sea ducks from anthropogenic threats.
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Affiliation(s)
- Kathleen A. McGrew
- Virginia Maryland College of Veterinary Medicine, 205 Duck Pond Drive, Blacksburg, VA 24060, USA
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Sarah E. Crowell
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Jonathan L. Fiely
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Alicia M. Berlin
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Glenn H. Olsen
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Jennifer James
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Heather Hopkins
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Christopher K. Williams
- Naval Undersea Warfare Center, Newport Division, Mission Environmental Planning, 1176 Howell St, Newport, RI 02841, USA
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Darby J, Clairbaux M, Bennison A, Quinn JL, Jessopp MJ. Underwater visibility constrains the foraging behaviour of a diving pelagic seabird. Proc Biol Sci 2022; 289:20220862. [PMID: 35858070 PMCID: PMC9277241 DOI: 10.1098/rspb.2022.0862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Understanding the sensory ecology of species is vital if we are to predict how they will function in a changing environment. Visual cues are fundamentally important for many predators when detecting and capturing prey. However, many marine areas have become more turbid through processes influenced by climate change, potentially affecting the ability of marine predators to detect prey. We performed the first study that directly relates a pelagic seabird species's foraging behaviour to oceanic turbidity. We collected biologging data from 79 foraging trips and 5472 dives of a visually dependent, pursuit-diving seabird, the Manx shearwater (Puffinus puffinus). Foraging behaviour was modelled against environmental variables affecting underwater visibility, including water turbidity, cloud cover and solar angle. Shearwaters were more likely to initiate area-restricted search and foraging dives in clearer waters. Underwater visibility also strongly predicted dive rate and depth, suggesting that fine-scale prey capture was constrained by the detectability of prey underwater. Our novel use of dynamic descriptors of underwater visibility suggests that visual cues are vital for underwater foraging. Our data indicate that climate change could negatively impact seabird populations by making prey more difficult to detect, compounded by the widely reported effects of reduced prey populations.
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Affiliation(s)
- J. Darby
- School of Biological, Environmental and Earth Sciences, University College Cork, Cork T23 N73K, Ireland,MaREI Centre for Energy, Climate and Marine, Environmental Research Institute, University College Cork, Cork P43 C573, Ireland
| | - M. Clairbaux
- School of Biological, Environmental and Earth Sciences, University College Cork, Cork T23 N73K, Ireland,MaREI Centre for Energy, Climate and Marine, Environmental Research Institute, University College Cork, Cork P43 C573, Ireland
| | - A. Bennison
- British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, UK
| | - J. L. Quinn
- School of Biological, Environmental and Earth Sciences, University College Cork, Cork T23 N73K, Ireland
| | - M. J. Jessopp
- School of Biological, Environmental and Earth Sciences, University College Cork, Cork T23 N73K, Ireland,MaREI Centre for Energy, Climate and Marine, Environmental Research Institute, University College Cork, Cork P43 C573, Ireland
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Sutton GJ, Arnould JPY. Quantity over quality? Prey-field characteristics influence the foraging decisions of little penguins ( Eudyptula minor). ROYAL SOCIETY OPEN SCIENCE 2022; 9:211171. [PMID: 35719883 PMCID: PMC9198507 DOI: 10.1098/rsos.211171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Quantifying prey characteristics is important for understanding the foraging behaviour of predators, which ultimately influence the structure and function of entire ecosystems. However, information available on prey is often at magnitudes which cannot be used to infer the fine-scale behaviour of predators, especially so in marine environments where direct observation of predator-prey interactions is rarely possible. In the present study, animal-borne video data loggers were used to determine the influence of prey type and patch density on the foraging behaviour of the little penguin (Eudyptula minor), an important predator in southeastern Australia. We found that numerical density positively influenced time spent foraging at a patch. However, when accounting for calorific value in density estimates, individuals spent longer at dense patches of low-quality prey. This may reflect a trade-off between capture effort and calorific gain as lower quality prey were captured at higher rates. During the breeding season, foraging trip distance and duration is constrained by the need to return to the colony each day to feed offspring. The results of the study suggest that, under these spatio-temporal constraints, little penguins maximize foraging performance by concentrating efforts at larger quantities of prey, irrespective of their calorific quality.
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Affiliation(s)
- G. J. Sutton
- School of Life and Environmental Sciences, Faculty of Science and Technology, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
| | - J. P. Y. Arnould
- School of Life and Environmental Sciences, Faculty of Science and Technology, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia
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Aquatic birds have middle ears adapted to amphibious lifestyles. Sci Rep 2022; 12:5251. [PMID: 35347167 PMCID: PMC8960762 DOI: 10.1038/s41598-022-09090-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/16/2022] [Indexed: 11/21/2022] Open
Abstract
Birds exhibit wide variation in their use of aquatic environments, on a spectrum from entirely terrestrial, through amphibious, to highly aquatic. Although there are limited empirical data on hearing sensitivity of birds underwater, mounting evidence indicates that diving birds detect and respond to sound underwater, suggesting that some modifications of the ear may assist foraging or other behaviors below the surface. In air, the tympanic middle ear acts as an impedance matcher that increases sound pressure and decreases sound vibration velocity between the outside air and the inner ear. Underwater, the impedance-matching task is reversed and the ear is exposed to high hydrostatic pressures. Using micro- and nano-CT (computerized tomography) scans of bird ears in 127 species across 26 taxonomic orders, we measured a suite of morphological traits of importance to aerial and aquatic hearing to test predictions relating to impedance-matching in birds with distinct aquatic lifestyles, while accounting for allometry and phylogeny. Birds that engage in underwater pursuit and deep diving showed the greatest differences in ear structure relative to terrestrial species. In these heavily modified ears, the size of the input areas of both the tympanic membrane and the columella footplate of the middle ear were reduced. Underwater pursuit and diving birds also typically had a shorter extrastapedius, a reduced cranial air volume and connectivity and several modifications in line with reversals of low-to-high impedance-matching. The results confirm adaptations of the middle ear to aquatic lifestyles in multiple independent bird lineages, likely facilitating hearing underwater and baroprotection, while potentially constraining the sensitivity of aerial hearing.
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7
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Parsons MJG, Lin TH, Mooney TA, Erbe C, Juanes F, Lammers M, Li S, Linke S, Looby A, Nedelec SL, Van Opzeeland I, Radford C, Rice AN, Sayigh L, Stanley J, Urban E, Di Iorio L. Sounding the Call for a Global Library of Underwater Biological Sounds. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.810156] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Aquatic environments encompass the world’s most extensive habitats, rich with sounds produced by a diversity of animals. Passive acoustic monitoring (PAM) is an increasingly accessible remote sensing technology that uses hydrophones to listen to the underwater world and represents an unprecedented, non-invasive method to monitor underwater environments. This information can assist in the delineation of biologically important areas via detection of sound-producing species or characterization of ecosystem type and condition, inferred from the acoustic properties of the local soundscape. At a time when worldwide biodiversity is in significant decline and underwater soundscapes are being altered as a result of anthropogenic impacts, there is a need to document, quantify, and understand biotic sound sources–potentially before they disappear. A significant step toward these goals is the development of a web-based, open-access platform that provides: (1) a reference library of known and unknown biological sound sources (by integrating and expanding existing libraries around the world); (2) a data repository portal for annotated and unannotated audio recordings of single sources and of soundscapes; (3) a training platform for artificial intelligence algorithms for signal detection and classification; and (4) a citizen science-based application for public users. Although individually, these resources are often met on regional and taxa-specific scales, many are not sustained and, collectively, an enduring global database with an integrated platform has not been realized. We discuss the benefits such a program can provide, previous calls for global data-sharing and reference libraries, and the challenges that need to be overcome to bring together bio- and ecoacousticians, bioinformaticians, propagation experts, web engineers, and signal processing specialists (e.g., artificial intelligence) with the necessary support and funding to build a sustainable and scalable platform that could address the needs of all contributors and stakeholders into the future.
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8
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Clairbaux M, Mathewson P, Porter W, Fort J, Strøm H, Moe B, Fauchald P, Descamps S, Helgason HH, Bråthen VS, Merkel B, Anker-Nilssen T, Bringsvor IS, Chastel O, Christensen-Dalsgaard S, Danielsen J, Daunt F, Dehnhard N, Erikstad KE, Ezhov A, Gavrilo M, Krasnov Y, Langset M, Lorentsen SH, Newell M, Olsen B, Reiertsen TK, Systad GH, Thórarinsson TL, Baran M, Diamond T, Fayet AL, Fitzsimmons MG, Frederiksen M, Gilchrist HG, Guilford T, Huffeldt NP, Jessopp M, Johansen KL, Kouwenberg AL, Linnebjerg JF, Major HL, Tranquilla LM, Mallory M, Merkel FR, Montevecchi W, Mosbech A, Petersen A, Grémillet D. North Atlantic winter cyclones starve seabirds. Curr Biol 2021; 31:3964-3971.e3. [PMID: 34520704 DOI: 10.1016/j.cub.2021.06.059] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/26/2021] [Accepted: 06/21/2021] [Indexed: 11/28/2022]
Abstract
Each winter, the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called "winter wrecks."1-3 During these, thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics4,5 by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear.6 We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community by coupling winter tracking data for ∼1,500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia, and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model7 and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high intensity impacted birds from all studied species and breeding colonies during winter but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland, and the Barents Sea. Our broad-scale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming.8.
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Affiliation(s)
- Manon Clairbaux
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul Valéry Montpellier 3, Montpellier, France.
| | - Paul Mathewson
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Warren Porter
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR7266 CNRS - La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | - Hallvard Strøm
- Norwegian Polar Institute, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
| | - Børge Moe
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Per Fauchald
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Sebastien Descamps
- Norwegian Polar Institute, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
| | - Hálfdán H Helgason
- Norwegian Polar Institute, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
| | - Vegard S Bråthen
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Benjamin Merkel
- Akvaplan-niva AS, Fram Centre, PO Box 6606 Langnes, 9296 Tromsø, Norway
| | - Tycho Anker-Nilssen
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Ingar S Bringsvor
- Norwegian Ornithological Society, Sandgata 30 B, 7012 Trondheim, Norway
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS/La Rochelle Univ, La Rochelle, France
| | | | - Jóhannis Danielsen
- Faroe Marine Research Institute, PO Box 3051, Nóatún 1, 110 Tórshavn, Faroe Islands
| | - Francis Daunt
- UK Centre for Ecology & Hydrology, Bush Estate, Penicuik EH26 0QB, UK
| | - Nina Dehnhard
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Kjell Einar Erikstad
- Norwegian Institute for Nature Research, Fram Centre, 9296 Tromsø, Norway; Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Alexey Ezhov
- Murmansk Marine Biological Institute, 17 Vladimirskaya Street, 183010 Murmansk, Russia
| | - Maria Gavrilo
- Association Maritime Heritage, Saint Petersburg, Russia; National Park Russian Arctic, 57 Sovetskikh Kosmonavtove Avenue, Archangelsk, Russia
| | - Yuri Krasnov
- Murmansk Marine Biological Institute, 17 Vladimirskaya Street, 183010 Murmansk, Russia
| | - Magdalene Langset
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Svein-H Lorentsen
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | - Mark Newell
- UK Centre for Ecology & Hydrology, Bush Estate, Penicuik EH26 0QB, UK
| | - Bergur Olsen
- Faroe Marine Research Institute, PO Box 3051, Nóatún 1, 110 Tórshavn, Faroe Islands
| | - Tone K Reiertsen
- Norwegian Institute for Nature Research, Fram Centre, 9296 Tromsø, Norway
| | - Geir Helge Systad
- Norwegian Institute for Nature Research - NINA, PO Box 5685 Torgarden, 7485 Trondheim, Norway
| | | | - Mark Baran
- Atlantic Laboratory for Avian Research, University of New Brunswick, PO Box 4400, Fredericton, NB E3B 5A3, Canada
| | - Tony Diamond
- Atlantic Laboratory for Avian Research, University of New Brunswick, PO Box 4400, Fredericton, NB E3B 5A3, Canada
| | - Annette L Fayet
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Michelle G Fitzsimmons
- Wildlife Research Division, Environment and Climate Change Canada, 6 Bruce Street, Mount Pearl, NL A1N 4T3, Canada
| | - Morten Frederiksen
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Hugh G Gilchrist
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, Canada
| | - Tim Guilford
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Nicholas P Huffeldt
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark; Greenland Institute of Natural Resources, Kivioq 2, 3900 Nuuk, Greenland
| | - Mark Jessopp
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Field, North Mall, Cork, Ireland; MaREI Centre, Environmental Research Inst., Univ. College Cork, Cork, Ireland
| | - Kasper L Johansen
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | | | - Jannie F Linnebjerg
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Heather L Major
- Department of Biological Sciences, University of New Brunswick, PO Box 5050, Saint John, NB E2L 4L5, Canada
| | | | - Mark Mallory
- Biology, Acadia University, 15 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Flemming R Merkel
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - William Montevecchi
- Psychology and Biology Departments, Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada
| | - Anders Mosbech
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | | | - David Grémillet
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS/La Rochelle Univ, La Rochelle, France; Percy FitzPatrick Institute, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa.
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9
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Cziko PA, Munger LM, Santos NR, Terhune JM. Weddell seals produce ultrasonic vocalizations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:3784. [PMID: 33379885 DOI: 10.1121/10.0002867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/11/2020] [Indexed: 06/12/2023]
Abstract
Seals (phocids) are generally not thought to produce vocalizations having ultrasonic fundamental frequencies (≥20 kHz), although previous studies could have been biased by sampling limitations. This study characterizes common, yet, previously undescribed, ultrasonic Weddell seal (Leptonychotes weddellii) vocalizations. The vocalizations were identified in more than one year (2017-2018) of broadband acoustic data obtained by a continuously recording underwater observatory in McMurdo Sound, Antarctica. Nine recurrent call types were identified that were composed of single or multiple vocal elements whose fundamental frequencies spanned the ultrasonic range to nearly 50 kHz. Eleven vocal elements had ultrasonic center frequencies (≥20 kHz), including chirps, whistles, and trills, with two elements at >30 kHz. Six elements had fundamental frequencies always >21 kHz. The fundamental frequency of one repetitive U-shaped whistle element reached 44.2 kHz and descending chirps (≥3.6 ms duration) commenced at ≤49.8 kHz. The source amplitude of one fully ultrasonic chirp element (29.5 kHz center frequency) was 137 dB re 1 μPa-m. Harmonics of some vocalizations exceeded 200 kHz. Ultrasonic vocalizations occurred throughout the year with the usage of repetitive ultrasonic chirp-based calls appearing to dominate in winter darkness. The functional significance of these high-frequency vocalizations is unknown.
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Affiliation(s)
- Paul A Cziko
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403-5289, USA
| | - Lisa M Munger
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403-5289, USA
| | - Nicholas R Santos
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403-5289, USA
| | - John M Terhune
- Department of Biological Sciences, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
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10
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Larsen ON, Wahlberg M, Christensen-Dalsgaard J. Amphibious hearing in a diving bird, the great cormorant ( Phalacrocorax carbo sinensis). J Exp Biol 2020; 223:jeb217265. [PMID: 32098879 DOI: 10.1242/jeb.217265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/10/2020] [Indexed: 11/20/2022]
Abstract
Diving birds can spend several minutes underwater during pursuit-dive foraging. To find and capture prey, such as fish and squid, they probably need several senses in addition to vision. Cormorants, very efficient predators of fish, have unexpectedly low visual acuity underwater. So, underwater hearing may be an important sense, as for other diving animals. We measured auditory thresholds and eardrum vibrations in air and underwater of the great cormorant (Phalacrocorax carbo sinensis). Wild-caught cormorant fledglings were anaesthetized, and their auditory brainstem response (ABR) and eardrum vibrations to clicks and tone bursts were measured, first in an anechoic box in air and then in a large water-filled tank, with their head and ears submerged 10 cm below the surface. Both the ABR waveshape and latency, as well as the ABR threshold, measured in units of sound pressure, were similar in air and water. The best average sound pressure sensitivity was found at 1 kHz, both in air (53 dB re. 20 µPa) and underwater (58 dB re. 20 µPa). When thresholds were compared in units of intensity, however, the sensitivity underwater was higher than in air. Eardrum vibration amplitude in both media reflected the ABR threshold curves. These results suggest that cormorants have in-air hearing abilities comparable to those of similar-sized diving birds, and that their underwater hearing sensitivity is at least as good as their aerial sensitivity. This, together with the morphology of the outer ear (collapsible meatus) and middle ear (thickened eardrum), suggests that cormorants may have anatomical and physiological adaptations for amphibious hearing.
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Affiliation(s)
- Ole Næsbye Larsen
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Magnus Wahlberg
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jakob Christensen-Dalsgaard
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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