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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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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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McInnes AM, McGeorge C, Ginsberg S, Pichegru L, Pistorius PA. Group foraging increases foraging efficiency in a piscivorous diver, the African penguin. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170918. [PMID: 28989785 PMCID: PMC5627125 DOI: 10.1098/rsos.170918] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/29/2017] [Indexed: 05/14/2023]
Abstract
Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change.
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Affiliation(s)
- Alistair M. McInnes
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, Summerstrand 6031, South Africa
- Author for correspondence: Alistair M. McInnes e-mail:
| | - Cuan McGeorge
- CapeNature, Stony Point, Betty's Bay 7141, South Africa
| | - Samuel Ginsberg
- Department of Electrical Engineering, University of Cape Town, Rondebosch 7701, South Africa
| | - Lorien Pichegru
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, Summerstrand 6031, South Africa
| | - Pierre A. Pistorius
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology, Nelson Mandela Metropolitan University, Summerstrand 6031, South Africa
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Favaro L, Gili C, Da Rugna C, Gnone G, Fissore C, Sanchez D, McElligott AG, Gamba M, Pessani D. Vocal individuality and species divergence in the contact calls of banded penguins. Behav Processes 2016; 128:83-8. [PMID: 27102762 DOI: 10.1016/j.beproc.2016.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 11/25/2022]
Abstract
Penguins produce contact calls to maintain social relationships and group cohesion. Such vocalisations have recently been demonstrated to encode individual identity information in the African penguin. Using a source-filter theory approach, we investigated whether acoustic cues of individuality can also be found in other Spheniscus penguins and the acoustic features of contact calls have diverged within this genus. We recorded vocalisations from two ex-situ colonies of Humboldt penguin and Magellanic penguin (sympatric and potentially interbreeding in the wild) and one ex-situ group of African penguins (allopatric although capable of interbreeding with the other two species in captivity). We measured 14 acoustic parameters from each vocalisation. These included temporal (duration), source-related (fundamental frequency, f0), and filter-related (formants) parameters. They were then used to carry out a series of stepwise discriminant function analyses (with cross-validation) and General Linear Model comparisons. We showed that contact calls allow individual discrimination in two additional species of the genus Spheniscus. We also found that calls can be classified according to species in a manner far greater than that attributable by chance, even though there is limited genetic distance among African, Humboldt, and Magellanic penguins. Our results provide further evidence that the source-filter theory is a valuable framework for investigating the biologically meaningful information contained in bird vocalisations. Our findings also provide novel insights into penguin vocal communication and suggest that contact calls of the penguin family are affected by selection for individuality.
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Affiliation(s)
- Livio Favaro
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.
| | - Claudia Gili
- Acquario di Genova, Costa Edutainment SpA, Genoa, Italy
| | | | - Guido Gnone
- Acquario di Genova, Costa Edutainment SpA, Genoa, Italy
| | - Chiara Fissore
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | | | - Alan G McElligott
- Queen Mary University of London, Biological and Experimental Psychology, School of Biological and Chemical Sciences, London, UK
| | - Marco Gamba
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Daniela Pessani
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
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Frost PGH, Siegfried WR, Burger AE. Behavioural adaptations of the Jackass penguin, Spheniscus demersus to a hot, arid environment. J Zool (1987) 2009. [DOI: 10.1111/j.1469-7998.1976.tb02289.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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A note on swimming group size in captive African penguins (Spheniscus demersus) in relation to weather conditions. Appl Anim Behav Sci 1999. [DOI: 10.1016/s0168-1591(98)00235-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Williams TD. Reproductive endocrinology of macaroni (Eudyptes chrysolophus) and gentoo (Pygoscelis papua) penguins. I. Seasonal changes in plasma levels of gonadal steroids and LH in breeding adults. Gen Comp Endocrinol 1992; 85:230-40. [PMID: 1601255 DOI: 10.1016/0016-6480(92)90006-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Changes in plasma luteinizing hormone (LH), testosterone, oestradiol, and progesterone were measured throughout the breeding and molt cycle in free-living male and female macaroni (Eudyptes chrysolophus) and gentoo (Pygoscelis papua) penguins, at Bird Island, South Georgia (54 degrees S, 38 degrees W). These two species are sympatric but have a markedly different breeding cycle. In macaroni penguins plasma levels of all hormones, except LH in males, were significantly elevated at the time of arrival at the breeding colony. In both species and sexes plasma LH, testosterone (males), and estradiol (females) levels were highest during nest-building and postcopulation, coincident with the period of frequent agonistic interactions in males and egg-formation in females. Elevated testosterone levels occurred in females of both species during the postcopulation period and may be associated behaviourally with both sexes being involved in nest defence. Male birds also had elevated estradiol levels. Following copulation, plasma levels of LH, testosterone, and estradiol decreased to basal levels in both sexes and species and, except for a transient increase in testosterone in male macaroni penguins, remained low through to the end of molt. There was no associated rise in LH or testosterone during premolt and early molt despite a further period of agonistic and social interaction, suggesting that birds were in a photorefractory state at this time. Plasma progesterone showed a pattern of variation different from that of the other hormones. In both species and sexes, plasma levels were elevated between arrival and early chick-rearing and then decreased slowly to low levels during molt.
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Affiliation(s)
- T D Williams
- British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
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HEATH RGM, RANDALL RM. Foraging ranges and movements of jackass penguins (Spheniscus demersus) established through radio telemetry. J Zool (1987) 1989. [DOI: 10.1111/j.1469-7998.1989.tb02496.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ryan PG, Wilson RP, Cooper J. Intraspecific mimicry and status signals in juvenile African penguins. Behav Ecol Sociobiol 1987. [DOI: 10.1007/bf00292167] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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