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Masud MH, Dabnichki P. Biomechanical analysis of little penguins' underwater locomotion from the free-ranging dive data. Biol Open 2024; 13:bio060244. [PMID: 38639412 PMCID: PMC11139039 DOI: 10.1242/bio.060244] [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: 11/17/2023] [Accepted: 04/15/2024] [Indexed: 04/20/2024] Open
Abstract
Penguins are proficient swimmers, and their survival depends on their ability to catch prey. The diving behaviour of these fascinating birds should then minimize the associated energy cost. For the first time, the energy cost of penguin dives is computed from the free-ranging dive data, on the basis of an existing biomechanical model. Time-resolved acceleration and depth data collected for 300 dives of little penguins (Eudyptula minor) are specifically employed to compute the bird dive angles and swimming speeds, which are needed for the energy estimate. We find that the numerically obtained energy cost by using the free-ranging dive data is not far from the minimum cost predicted by the model. The outcome, therefore, supports the physical soundness of the chosen model; however, it also suggests that, for closer agreement, one should consider previously neglected effects, such as those due to water currents and those associated with motion unsteadiness. Additionally, from the free-ranging dive data, we calculate hydrodynamic forces and non-dimensional indicators of propulsion performance - Strouhal and Reynolds numbers. The obtained values further confirm that little penguins employ efficient propulsion mechanisms, in agreement with previous investigations.
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Affiliation(s)
- Mahadi Hasan Masud
- Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi 6204, Bangladesh
| | - Peter Dabnichki
- School of Engineering, RMIT University, Bundoora Campus, Melbourne, VIC,Australia3083
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2
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Pulvirenti J, Reina RD, Chiaradia A. Exploring subcolony differences in foraging and reproductive success: the influence of environmental conditions on a central place foraging seabird. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220362. [PMID: 37388318 PMCID: PMC10300673 DOI: 10.1098/rsos.220362] [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: 03/22/2022] [Accepted: 06/07/2023] [Indexed: 07/01/2023]
Abstract
While differences in foraging and reproductive success are well studied between seabird colonies, they are less understood at a smaller subcolony scale. Working with little penguins (Eudyptula minor) at Phillip Island, Australia, we used an automated penguin monitoring system and performed regular nest checks at two subcolonies situated 2 km apart during the 2015/2016 breeding seasons. We examined whether foraging and reproductive success differed between subcolonies. We used satellite data to examine how sea surface temperature, as environmental pressure, in the foraging regions from each subcolony influenced their foraging performance. In the pre-laying and incubation breeding stages, the birds from one subcolony had a lower foraging success than birds from the other. However, this pattern was reversed between the subcolonies in the guard and post-guard stages. Breeding success data from the two subcolonies from 2004-2018 showed that reproductive success and mean egg-laying had a negative relationship with sea surface temperature. We highlighted that variation in foraging and reproductive success can arise in subcolonies, likely due to different responses to environmental conditions and prey availability. Differences at the subcolony level can help refine, develop and improve appropriate species management plans for conserving a range of colonial central place seabirds.
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Affiliation(s)
- Jessica Pulvirenti
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Richard D. Reina
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Andre Chiaradia
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
- Conservation Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
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3
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Lescroël A, Schmidt A, Ainley DG, Dugger KM, Elrod M, Jongsomjit D, Morandini V, Winquist S, Ballard G. High-resolution recording of foraging behaviour over multiple annual cycles shows decline in old Adélie penguins' performance. Proc Biol Sci 2023; 290:20222480. [PMID: 37015277 PMCID: PMC10072935 DOI: 10.1098/rspb.2022.2480] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/06/2023] [Indexed: 04/06/2023] Open
Abstract
Age-related variation in foraging performance can result from both within-individual change and selection processes. These mechanisms can only be disentangled by using logistically challenging long-term, longitudinal studies. Coupling a long-term demographic data set with high-temporal-resolution tracking of 18 Adélie penguins (Pygoscelis adeliae, age 4-15 yrs old) over three consecutive annual cycles, we examined how foraging behaviour changed within individuals of different age classes. Evidence indicated within-individual improvement in young and middle-age classes, but a significant decrease in foraging dive frequency within old individuals, associated with a decrease in the dive descent rate. Decreases in foraging performance occurred at a later age (from 12-15 yrs old to 15-18 yrs old) than the onset of senescence predicted for this species (9-11 yrs old). Foraging dive frequency was most affected by the interaction between breeding status and annual life-cycle periods, with frequency being highest during returning migration and breeding season and was highest overall for successful breeders during the chick-rearing period. Females performed more foraging dives per hour than males. This longitudinal, full annual cycle study allowed us to shed light on the changes in foraging performance occurring among individuals of different age classes and highlighted the complex interactions among drivers of individual foraging behaviour.
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Affiliation(s)
| | - Annie Schmidt
- Point Blue Conservation Science, Petaluma, CA 94954, USA
| | - David G. Ainley
- H. T. Harvey & Associates Ecological Consultants, Los Gatos, CA 95032, USA
| | - Katie M. Dugger
- US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR 97333, USA
| | - Megan Elrod
- Point Blue Conservation Science, Petaluma, CA 94954, USA
| | | | - Virginia Morandini
- Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, 104 Nash Hall, Corvallis, OR 97331, USA
- Fundación Migres, CIMA, N-340km 85, E-11380 Tarifa, Spain
- Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal, 2, 28006 Madrid, Spain
| | - Suzanne Winquist
- Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Hatfield Marine Science Center, Newport, OR 97365, USA
| | - Grant Ballard
- Point Blue Conservation Science, Petaluma, CA 94954, USA
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4
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Masello JF, Rast W, Schumm YR, Metzger B, Quillfeldt P. Year-round behavioural time budgets of common woodpigeons inferred from acceleration data using machine learning. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-023-03306-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Abstract
Accelerometers capture rapid changes in animal motion, and the analysis of large quantities of such data using machine learning algorithms enables the inference of broad animal behaviour categories such as foraging, flying, and resting over long periods of time. We deployed GPS-GSM/GPRS trackers with tri-axial acceleration sensors on common woodpigeons (Columba palumbus) from Hesse, Germany (forest and urban birds) and from Lisbon, Portugal (urban park). We used three machine learning algorithms, Random Forest, Support Vector Machine, and Extreme Gradient Boosting, to classify the main behaviours of the birds, namely foraging, flying, and resting and calculated time budgets over the breeding and winter season. Woodpigeon time budgets varied between seasons, with more foraging time during the breeding season than in winter. Also, woodpigeons from different sites showed differences in the time invested in foraging. The proportion of time woodpigeons spent foraging was lowest in the forest habitat from Hesse, higher in the urban habitat of Hesse, and highest in the urban park in Lisbon. The time budgets we recorded contrast to previous findings in woodpigeons and reaffirm the importance of considering different populations to fully understand the behaviour and adaptation of a particular species to a particular environment. Furthermore, the differences in the time budgets of Woodpigeons from this study and previous ones might be related to environmental change and merit further attention and the future investigation of energy budgets.
Significance statement
In this study we took advantage of accelerometer technology and machine learning methods to investigate year-round behavioural time budgets of wild common woodpigeons (Columba palumbus). Our analysis focuses on identifying coarse-scale behaviours (foraging, flying, resting) using various machine learning algorithms. Woodpigeon time budgets varied between seasons and among sites. Particularly interesting is the result showing that urban woodpigeons spend more time foraging than forest conspecifics. Our study opens an opportunity to further investigate and understand how a successful bird species such as the woodpigeon copes with increasing environmental change and urbanisation. The increase in the proportion of time devoted to foraging might be one of the behavioural mechanisms involved but opens questions about the costs associated to such increase in terms of other important behaviours.
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Saraux C, Chiaradia A. Age‐related breeding success in little penguins: a result of selection and ontogenetic changes in foraging and phenology. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Claire Saraux
- DEPE UMR7178 IPHC CNRS‐Université de Strasbourg 23 rue du Loess 67037 Strasbourg France
| | - Andre Chiaradia
- Conservation Department Phillip Island Nature Parks PO Box 97 Cowes Victoria 3922 Australia
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6
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Barreau E, Kato A, Chiaradia A, Ropert-Coudert Y. The consequences of chaos: Foraging activity of a marine predator remains impacted several days after the end of a storm. PLoS One 2021; 16:e0254269. [PMID: 34242336 PMCID: PMC8270419 DOI: 10.1371/journal.pone.0254269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 06/24/2021] [Indexed: 11/22/2022] Open
Abstract
As extreme weather is expected to become more frequent with global climate change, it is crucial to evaluate the capacity of species to respond to short-term and unpredictable events. Here, we examined the effect of a strong storm event during the chick-rearing stage of little penguins (Eudyptula minor) from a mega colony in southern Australia. We investigated how a 3-day storm affected the foraging behaviour of little penguins by comparing their foraging activities and body mass change before, during and after the storm event. As strong winds deepened the mixed layer in the birds’ foraging zone during the storm, penguins increased their foraging trip duration, had a lower prey encounter rate and a lower body mass gain. The adverse effects on the foraging efficiency of little penguins continued several days after the storm ceased; even though the water column stratification had returned as before the storm, suggesting a prolonged effect of the storm event on the prey availability. Thus, short-term stochastic events can have an extended impact on the foraging efficiency of penguins. When occurring at a crucial stage of breeding, this may affect breeding success.
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Affiliation(s)
- Emmanuelle Barreau
- Centre d’Études Biologiques de Chizé, UMR 7372 CNRS—La Rochelle Université, Villiers en Bois, France
- * E-mail:
| | - Akiko Kato
- Centre d’Études Biologiques de Chizé, UMR 7372 CNRS—La Rochelle Université, Villiers en Bois, France
| | - Andre Chiaradia
- Conservation Department, Phillip Island Nature Parks, Cowes, VIC, Australia
| | - Yan Ropert-Coudert
- Centre d’Études Biologiques de Chizé, UMR 7372 CNRS—La Rochelle Université, Villiers en Bois, France
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7
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How king penguins advertise their sexual maturity. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Enstipp MR, Bost CA, Le Bohec C, Chatelain N, Weimerskirch H, Handrich Y. The early life of king penguins: ontogeny of dive capacity and foraging behaviour in an expert diver. J Exp Biol 2021; 224:269166. [PMID: 34132335 DOI: 10.1242/jeb.242512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022]
Abstract
The period of emancipation in seabirds, when juveniles change from a terrestrial existence to a life at sea, is associated with many challenges. Apart from finding favourable foraging sites, they have to develop effective prey search patterns and physiological capacities that enable them to capture sufficient prey to meet their energetic needs. Animals that dive to forage, such as king penguins (Aptenodytes patagonicus), need to acquire an adequate breath-hold capacity, allowing them to locate and capture prey at depth. To investigate the ontogeny of their dive capacity and foraging performance, we implanted juvenile king penguins before their first departure to sea and also adult breeders with a data-logger recording pressure and temperature. We found that juvenile king penguins possess a remarkable dive capacity when leaving their natal colony, enabling them to conduct dives in excess of 100 m within their first week at sea. Despite this, juvenile dive/foraging performance, investigated in relation to dive depth, remained below the adult level throughout their first year at sea, probably reflecting physiological limitations as a result of incomplete maturation. A significantly shallower foraging depth of juveniles, particularly during their first 5 months at sea, could also indicate differences in foraging strategy and targeted prey. The initially greater wiggle rate suggests that juveniles fed opportunistically and also targeted different prey from adults and/or that many of the wiggles of juveniles reflect unsuccessful prey-capture attempts, indicating a lower foraging proficiency. After 5 months, this difference disappeared, suggesting sufficient physical maturation and improvement of juvenile foraging skills.
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Affiliation(s)
- Manfred R Enstipp
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France.,Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Charles-André Bost
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Céline Le Bohec
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France.,Centre Scientifique de Monaco, Département de Biologie Polaire, MC 98000, Monaco
| | - Nicolas Chatelain
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Henri Weimerskirch
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Yves Handrich
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
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9
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Ramírez F, Chiaradia A, O'Leary DA, Reina RD. Making the most of the old age: Autumn breeding as an extra reproductive investment in older seabirds. Ecol Evol 2021; 11:5393-5401. [PMID: 34026015 PMCID: PMC8131812 DOI: 10.1002/ece3.7431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/11/2021] [Accepted: 03/01/2021] [Indexed: 02/05/2023] Open
Abstract
The extrinsic and intrinsic factors affecting differing reproductive strategies among populations are central to understanding population and evolutionary ecology. To evaluate whether individual reproductive strategies responded to annual patterns in marine productivity and age-related processes in a seabird we used a long term (2003-2013), a continuous dataset on nest occupancy and attendance at the colony by little penguins (Eudyptula minor) at Phillip Island (Victoria, Australia). We found that concurrent with a secondary annual peak of marine productivity, a secondary peak in colony attendance and nest occupancy was observed in Autumn (out of the regular breeding season in spring/summer) with individuals showing mating-like behavior. Individuals attending this autumn peak averaged 2.5 years older than those individuals that exclusively bred during spring/summer. Rather than being a naïve response by younger and inexperienced birds misreading environmental cues, our data indicate that the autumn peak attendance is an earlier attempt to breed by older and more experienced penguins. Therefore, we provide strong support for the fundamental prediction of the life-history theory of increasing investment in reproduction with age to maximize lifetime fitness as future survival prospects diminish and experience increases.
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Affiliation(s)
- Francisco Ramírez
- Department of Renewable Marine ResourcesInstitut de Ciències del Mar (ICM‐CSIC)BarcelonaSpain
| | - Andre Chiaradia
- School of Biological SciencesMonash UniversityClaytonVICAustralia
- Conservation DepartmentPhillip Island Nature ParksCowesVICAustralia
| | | | - Richard D. Reina
- School of Biological SciencesMonash UniversityClaytonVICAustralia
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10
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Hammers M, Kingma SA, van Boheemen LA, Sparks AM, Burke T, Dugdale HL, Richardson DS, Komdeur J. Helpers compensate for age-related declines in parental care and offspring survival in a cooperatively breeding bird. Evol Lett 2021; 5:143-153. [PMID: 33868710 PMCID: PMC8045936 DOI: 10.1002/evl3.213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/25/2020] [Accepted: 12/18/2020] [Indexed: 11/05/2022] Open
Abstract
Offspring from elderly parents often have lower survival due to parental senescence. In cooperatively breeding species, where offspring care is shared between breeders and helpers, the alloparental care provided by helpers is predicted to mitigate the impact of parental senescence on offspring provisioning and, subsequently, offspring survival. We test this prediction using data from a long-term study on cooperatively breeding Seychelles warblers (Acrocephalus sechellensis). We find that the nestling provisioning rate of female breeders declines with their age. Further, the total brood provisioning rate and the first-year survival probability of offspring decline progressively with age of the female breeder, but these declines are mitigated when helpers are present. This effect does not arise because individual helpers provide more care in response to the lower provisioning of older dominant females, but because older female breeders have recruited more helpers, thereby receiving more overall care for their brood. We do not find such effects for male breeders. These results indicate that alloparental care can alleviate the fitness costs of senescence for breeders, which suggests an interplay between age and cooperative breeding.
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Affiliation(s)
- Martijn Hammers
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenCP9712The Netherlands
| | - Sjouke A. Kingma
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenCP9712The Netherlands
- Department of Animal ScienceWageningen University & ResearchWageningenPB6708The Netherlands
| | - Lotte A. van Boheemen
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenCP9712The Netherlands
- School of Biological SciencesMonash UniversityClaytonVIC3800Australia
| | | | - Terry Burke
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldS10 2TNUnited Kingdom
| | | | - David S. Richardson
- School of Biological SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
- Nature SeychellesMahéRepublic of Seychelles
| | - Jan Komdeur
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenCP9712The Netherlands
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11
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Brown TJ, Hammers M, Taylor M, Dugdale HL, Komdeur J, Richardson DS. Hematocrit, age, and survival in a wild vertebrate population. Ecol Evol 2021; 11:214-226. [PMID: 33437424 PMCID: PMC7790625 DOI: 10.1002/ece3.7015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022] Open
Abstract
Understanding trade-offs in wild populations is difficult, but important if we are to understand the evolution of life histories and the impact of ecological variables upon them. Markers that reflect physiological state and predict future survival would be of considerable benefit to unraveling such trade-offs and could provide insight into individual variation in senescence. However, currently used markers often yield inconsistent results. One underutilized measure is hematocrit, the proportion of blood comprising erythrocytes, which relates to the blood's oxygen-carrying capacity and viscosity, and to individual endurance. Hematocrit has been shown to decline with age in cross-sectional studies (which may be confounded by selective appearance/disappearance). However, few studies have tested whether hematocrit declines within individuals or whether low hematocrit impacts survival in wild taxa. Using longitudinal data from the Seychelles warbler (Acrocephalus sechellensis), we demonstrated that hematocrit increases with age in young individuals (<1.5 years) but decreases with age in older individuals (1.5-13 years). In breeders, hematocrit was higher in males than females and varied relative to breeding stage. High hematocrit was associated with lower survival in young individuals, but not older individuals. Thus, while we did not find support for hematocrit as a marker of senescence, high hematocrit is indicative of poor condition in younger individuals. Possible explanations are that these individuals were experiencing dehydration and/or high endurance demands prior to capture, which warrants further investigation. Our study demonstrates that hematocrit can be an informative metric for life-history studies investigating trade-offs between survival, longevity, and reproduction.
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Affiliation(s)
- Thomas J. Brown
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Martijn Hammers
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Martin Taylor
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Hannah L. Dugdale
- School of BiologyFaculty of Biological SciencesUniversity of LeedsLeedsUK
| | - Jan Komdeur
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - David S. Richardson
- School of Biological SciencesUniversity of East AngliaNorwichUK
- Nature SeychellesVictoriaMahéSeychelles
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12
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Gunner RM, Wilson RP, Holton MD, Scott R, Hopkins P, Duarte CM. A new direction for differentiating animal activity based on measuring angular velocity about the yaw axis. Ecol Evol 2020; 10:7872-7886. [PMID: 32760571 PMCID: PMC7391348 DOI: 10.1002/ece3.6515] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 12/11/2022] Open
Abstract
The use of animal-attached data loggers to quantify animal movement has increased in popularity and application in recent years. High-resolution tri-axial acceleration and magnetometry measurements have been fundamental in elucidating fine-scale animal movements, providing information on posture, traveling speed, energy expenditure, and associated behavioral patterns. Heading is a key variable obtained from the tandem use of magnetometers and accelerometers, although few field investigations have explored fine-scale changes in heading to elucidate differences in animal activity (beyond the notable exceptions of dead-reckoning).This paper provides an overview of the value and use of animal heading and a prime derivative, angular velocity about the yaw axis, as an important element for assessing activity extent with potential to allude to behaviors, using "free-ranging" Loggerhead turtles (Caretta caretta) as a model species.We also demonstrate the value of yaw rotation for assessing activity extent, which varies over the time scales considered and show that various scales of body rotation, particularly rate of change of yaw, can help resolve differences between fine-scale behavior-specific movements. For example, oscillating yaw movements about a central point of the body's arc implies bouts of foraging, while unusual circling behavior, indicative of conspecific interactions, could be identified from complete revolutions of the longitudinal axis.We believe this approach should help identification of behaviors and "space-state" approaches to enhance our interpretation of behavior-based movements, particularly in scenarios where acceleration metrics have limited value, such as for slow-moving animals.
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Affiliation(s)
- Richard M. Gunner
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Rory P. Wilson
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Mark D. Holton
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Rebecca Scott
- Future Ocean Cluster of ExcellenceGEOMAR Helmholtz Centre for Ocean ResearchKielGermany
- Natural Environmental Research Council, Polaris HouseSwindonUK
| | - Phil Hopkins
- Swansea Lab for Animal Movement, BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Carlos M. Duarte
- Red Sea Research CentreKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
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13
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De La Torre GM, Freitas FF, Fratoni RDO, Guaraldo ADC, Dutra DDA, Braga M, Manica LT. Hemoparasites and their relation to body condition and plumage coloration of the White-necked thrush (Turdus albicollis). ETHOL ECOL EVOL 2020. [DOI: 10.1080/03949370.2020.1769739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Gabriel Massaccesi De La Torre
- Programa de Pós-graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
- Laboratório de Ecologia Comportamental e Ornitologia, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
| | - Fernando Ferneda Freitas
- Laboratório de Ecologia Comportamental e Ornitologia, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
- Programa de Pós-graduação em Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
| | - Rafael De Oliveira Fratoni
- Programa de Pós-graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
- Laboratório de Ecologia Comportamental e Ornitologia, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
| | - André De Camargo Guaraldo
- Programa de Pós-graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
- Laboratório de Ecologia Comportamental e Ornitologia, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
- Departamento de Zoologia, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Brazil
| | - Daniela De Angeli Dutra
- Programa de Pós-graduação em Ecologia, Conservação e Manejo da Vida Silvestre, Universidade Federal de Minas Gerais, Belo Horizonte 31270 901, Brazil
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270 901, Brazil
| | - M. Braga
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270 901, Brazil
| | - Lilian Tonelli Manica
- Laboratório de Ecologia Comportamental e Ornitologia, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba 81530 900, Brazil
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14
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Rast W, Kimmig SE, Giese L, Berger A. Machine learning goes wild: Using data from captive individuals to infer wildlife behaviours. PLoS One 2020; 15:e0227317. [PMID: 32369485 PMCID: PMC7200095 DOI: 10.1371/journal.pone.0227317] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/29/2020] [Indexed: 11/19/2022] Open
Abstract
1. Remotely tracking distinct behaviours of animals using acceleration data and machine learning has been carried out successfully in several species in captive settings. In order to study the ecology of animals in natural habitats, such behaviour classification models need to be transferred to wild individuals. However, at present, the development of those models usually requires direct observation of the target animals. 2. The goal of this study was to infer the behaviour of wild, free-roaming animals from acceleration data by training behaviour classification models on captive individuals, without the necessity to observe their wild conspecifics. We further sought to develop methods to validate the credibility of the resulting behaviour extrapolations. 3. We trained two machine learning algorithms proposed by the literature, Random Forest (RF) and Support Vector Machine (SVM), on data from captive red foxes (Vulpes vulpes) and later applied them to data from wild foxes. We also tested a new advance for behaviour classification, by applying a moving window to an Artificial Neural Network (ANN). Finally, we investigated four strategies to validate our classification output. 4. While all three machine learning algorithms performed well under training conditions (Kappa values: RF (0.82), SVM (0.78), ANN (0.85)), the established methods, RF and SVM, failed in classifying distinct behaviours when transferred from captive to wild foxes. Behaviour classification with the ANN and a moving window, in contrast, inferred distinct behaviours and showed consistent results for most individuals. 5. Our approach is a substantial improvement over the methods previously proposed in the literature as it generated plausible results for wild fox behaviour. We were able to infer the behaviour of wild animals that have never been observed in the wild and to further illustrate the credibility of the output. This framework is not restricted to foxes but can be applied to infer the behaviour of many other species and thus empowers new advances in behavioural ecology.
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Affiliation(s)
- Wanja Rast
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Sophia Elisabeth Kimmig
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Lisa Giese
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Anne Berger
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- * E-mail:
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15
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Campioni L, Dias MP, Granadeiro JP, Catry P. An ontogenetic perspective on migratory strategy of a long‐lived pelagic seabird: Timings and destinations change progressively during maturation. J Anim Ecol 2019; 89:29-43. [DOI: 10.1111/1365-2656.13044] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 05/10/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Letizia Campioni
- MARE – Marine and Environmental Sciences Center ISPA – Instituto Universitário Lisboa Portugal
| | - Maria Peixe Dias
- MARE – Marine and Environmental Sciences Center ISPA – Instituto Universitário Lisboa Portugal
- Birdlife International Cambridge UK
| | - José Pedro Granadeiro
- Departamento de Biologia Animal, CESAM Faculdade de Ciências da Universidade de Lisboa Lisboa Portugal
| | - Paulo Catry
- MARE – Marine and Environmental Sciences Center ISPA – Instituto Universitário Lisboa Portugal
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16
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Gownaris NJ, Boersma PD. Sex-biased survival contributes to population decline in a long-lived seabird, the Magellanic Penguin. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01826. [PMID: 30601594 PMCID: PMC6849821 DOI: 10.1002/eap.1826] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/12/2018] [Accepted: 10/16/2018] [Indexed: 05/29/2023]
Abstract
We developed a Hidden Markov mark-recapture model (R package marked) to examine sex-specific demography in Magellanic Penguins (Spheniscus magellanicus). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex-specific vital rates in demographic seabird studies. Like many other seabirds, Magellanic Penguins are long-lived, serially monogamous, and exhibit obligate biparental care. We found that the non-breeding-season survival of females was lower than that of males and that the magnitude of this bias was highest for juveniles. Biases in survival accumulated as cohorts aged, leading to increasingly skewed sex ratios. The survival bias was greatest in years when overall survival was low, that is, females fared disproportionality worse when conditions were unfavorable. Our model-estimated survival patterns are consistent with independent data on carcasses from the species' non-breeding grounds, showing that mortality is higher for juveniles than for adults and higher for females than for males. Juveniles may be less efficient foragers than adults are and, because of their smaller size, females may show less resilience to food scarcity than males. We used perturbation analysis of a population matrix model to determine the impact of sex-biased survival on adult sex ratio and population growth rate at Punta Tombo. We found that adult sex ratio and population growth rate have the greatest proportional response, that is, elasticity, to female pre-breeder and adult survival. Sex bias in juvenile survival (i.e., lower survival of females) made the greatest contribution to population declines from 1990 to 2009. Because starvation is a leading cause of morality in juveniles and adults, precautionary fisheries and spatial management in the region could help to slow population decline. Our data add to growing evidence that knowledge of sex-specific demography and sex ratios are necessary for accurate assessment of seabird population trends.
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Affiliation(s)
- N. J. Gownaris
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
| | - P. D. Boersma
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
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17
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Gilmour ME, Castillo-Guerrero JA, Fleishman AB, Hernández-Vázquez S, Young HS, Shaffer SA. Plasticity of foraging behaviors in response to diverse environmental conditions. Ecosphere 2018. [DOI: 10.1002/ecs2.2301] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Morgan E. Gilmour
- Ocean Sciences Department; University of California Santa Cruz; Santa Cruz California 95060 USA
| | - José A. Castillo-Guerrero
- CONACYT-Universidad de Guadalajara; Centro Universitario de la Costa Sur; San Patricio - Melaque Cihuatlán Jalisco 48980 México
| | - Abram B. Fleishman
- Department of Biological Sciences; San Jose State University; San Jose California 95192 USA
- Conservation Metrics, Inc.; 145 McAllister Way Santa Cruz California 95060 USA
| | - Salvador Hernández-Vázquez
- Departamento de Estudios para el Desarrollo Sustentable de Zona Costera; Centro Universitario de la Costa Sur; Universidad de Guadalajara; Gómez Farías No. 82 San Patricio-Melaque Cihuatlán Jalisco 48980 México
| | - Hillary S. Young
- Department of Ecology, Evolution, and Marine Biology; University of California Santa Barbara; Santa Barbara California 93106 USA
| | - Scott A. Shaffer
- Department of Biological Sciences; San Jose State University; San Jose California 95192 USA
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18
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Clay TA, Pearmain EJ, McGill RAR, Manica A, Phillips RA. Age‐related variation in non‐breeding foraging behaviour and carry‐over effects on fitness in an extremely long‐lived bird. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13120] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas A. Clay
- British Antarctic SurveyNatural Environment Research Council Cambridge UK
- Department of ZoologyUniversity of Cambridge Cambridge UK
| | | | - Rona A. R. McGill
- NERC Life Sciences Mass Spectrometry FacilityScottish Universities Environmental Research Centre East Kilbride UK
| | - Andrea Manica
- Department of ZoologyUniversity of Cambridge Cambridge UK
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19
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Hennin HL, Dey CJ, Bêty J, Gilchrist HG, Legagneux P, Williams TD, Love OP. Higher rates of prebreeding condition gain positively impacts clutch size: A mechanistic test of the condition‐dependent individual optimization model. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13133] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Holly L. Hennin
- Department of Biological SciencesUniversity of Windsor Windsor Ontario Canada
| | - Cody J. Dey
- Great Lakes Institute for Environmental ResearchUniversity of Windsor Windsor Ontario Canada
| | - Joël Bêty
- Département de Biologie and Centre d'études nordiquesUniversité du Québec à Rimouski Rimouski Québec Canada
| | - H. Grant Gilchrist
- National Wildlife Research CentreEnvironment and Climate Change Canada Ottawa Ontario Canada
| | - Pierre Legagneux
- Département de Biologie and Centre d'études nordiquesUniversité du Québec à Rimouski Rimouski Québec Canada
| | - Tony D. Williams
- Department of Biological SciencesSimon Fraser University Burnaby British Columbia Canada
| | - Oliver P. Love
- Department of Biological SciencesUniversity of Windsor Windsor Ontario Canada
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20
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Slagsvold T, Wiebe KL. Immigrants and locally recruited birds differ in prey delivered to their offspring in blue tits and great tits. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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21
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Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin. PLoS One 2017; 12:e0184114. [PMID: 28910405 PMCID: PMC5598940 DOI: 10.1371/journal.pone.0184114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/18/2017] [Indexed: 11/25/2022] Open
Abstract
Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.
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22
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Mattern T, Meyer S, Ellenberg U, Houston DM, Darby JT, Young M, van Heezik Y, Seddon PJ. Quantifying climate change impacts emphasises the importance of managing regional threats in the endangered Yellow-eyed penguin. PeerJ 2017; 5:e3272. [PMID: 28533952 PMCID: PMC5436559 DOI: 10.7717/peerj.3272] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/28/2017] [Indexed: 11/20/2022] Open
Abstract
Climate change is a global issue with effects that are difficult to manage at a regional scale. Yet more often than not climate factors are just some of multiple stressors affecting species on a population level. Non-climatic factors—especially those of anthropogenic origins—may play equally important roles with regard to impacts on species and are often more feasible to address. Here we assess the influence of climate change on population trends of the endangered Yellow-eyed penguin (Megadyptes antipodes) over the last 30 years, using a Bayesian model. Sea surface temperature (SST) proved to be the dominating factor influencing survival of both adult birds and fledglings. Increasing SST since the mid-1990s was accompanied by a reduction in survival rates and population decline. The population model showed that 33% of the variation in population numbers could be explained by SST alone, significantly increasing pressure on the penguin population. Consequently, the population becomes less resilient to non-climate related impacts, such as fisheries interactions, habitat degradation and human disturbance. However, the extent of the contribution of these factors to declining population trends is extremely difficult to assess principally due to the absence of quantifiable data, creating a discussion bias towards climate variables, and effectively distracting from non-climate factors that can be managed on a regional scale to ensure the viability of the population.
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Affiliation(s)
- Thomas Mattern
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Stefan Meyer
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Ursula Ellenberg
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Australia
| | - David M Houston
- Science and Policy Group, Department of Conservation, Auckland, New Zealand
| | | | - Melanie Young
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | | | - Philip J Seddon
- Department of Zoology, University of Otago, Dunedin, New Zealand
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23
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Reduced activity in middle-aged thick-billed murres: evidence for age related trends in fine-scale foraging behaviour. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Chilvers BL. Comparison of New Zealand’s little blue penguins, Eudyptula minor, diving behaviour. Polar Biol 2017. [DOI: 10.1007/s00300-017-2112-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Chimienti M, Cornulier T, Owen E, Bolton M, Davies IM, Travis JMJ, Scott BE. The use of an unsupervised learning approach for characterizing latent behaviors in accelerometer data. Ecol Evol 2016; 6:727-41. [PMID: 26865961 PMCID: PMC4739568 DOI: 10.1002/ece3.1914] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 11/11/2022] Open
Abstract
The recent increase in data accuracy from high resolution accelerometers offers substantial potential for improved understanding and prediction of animal movements. However, current approaches used for analysing these multivariable datasets typically require existing knowledge of the behaviors of the animals to inform the behavioral classification process. These methods are thus not well‐suited for the many cases where limited knowledge of the different behaviors performed exist. Here, we introduce the use of an unsupervised learning algorithm. To illustrate the method's capability we analyse data collected using a combination of GPS and Accelerometers on two seabird species: razorbills (Alca torda) and common guillemots (Uria aalge). We applied the unsupervised learning algorithm Expectation Maximization to characterize latent behavioral states both above and below water at both individual and group level. The application of this flexible approach yielded significant new insights into the foraging strategies of the two study species, both above and below the surface of the water. In addition to general behavioral modes such as flying, floating, as well as descending and ascending phases within the water column, this approach allowed an exploration of previously unstudied and important behaviors such as searching and prey chasing/capture events. We propose that this unsupervised learning approach provides an ideal tool for the systematic analysis of such complex multivariable movement data that are increasingly being obtained with accelerometer tags across species. In particular, we recommend its application in cases where we have limited current knowledge of the behaviors performed and existing supervised learning approaches may have limited utility.
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Affiliation(s)
- Marianna Chimienti
- School of Biological Sciences University of Aberdeen Tillydrone Avenue Aberdeen AB24 2TZ UK; Marine Scotland Science Scottish Government Marine Laboratory PO Box 101375 Victoria Road Aberdeen AB11 9DB UK
| | - Thomas Cornulier
- School of Biological Sciences University of Aberdeen Tillydrone Avenue Aberdeen AB24 2TZ UK
| | - Ellie Owen
- RSPB Centre for Conservation Science North Scotland Office Etive House, Beechwood Park Inverness IV2 6AL UK
| | - Mark Bolton
- RSPB Centre for Conservation Science The Lodge Sandy Bedfordshire SG19 2DL UK
| | - Ian M Davies
- Marine Scotland Science Scottish Government Marine Laboratory PO Box 101 375 Victoria Road Aberdeen AB11 9DB UK
| | - Justin M J Travis
- School of Biological Sciences University of Aberdeen Tillydrone Avenue Aberdeen AB24 2TZ UK
| | - Beth E Scott
- School of Biological Sciences University of Aberdeen Tillydrone Avenue Aberdeen AB24 2TZ UK
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26
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Thiebault A, Semeria M, Lett C, Tremblay Y. How to capture fish in a school? Effect of successive predator attacks on seabird feeding success. J Anim Ecol 2015; 85:157-67. [PMID: 26768335 DOI: 10.1111/1365-2656.12455] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 09/29/2015] [Indexed: 11/28/2022]
Abstract
Prey aggregations, such as fish schools, attract numerous predators. This typically leads to the formation of multispecific groups of predators. These aggregations can be seen both as a place of increased competition and as a place of possible facilitation between predators. Consequently, the functional role of such predator-prey aggregation is uncertain, and its effect on individual feeding success is virtually unknown. Using underwater film footage of different predators feeding on fish schools during the sardine run in South Africa, we directly measured the in situ feeding success of individual Cape gannets Morus capensis in different foraging situations. We determined the types of Cape gannet attacks (direct plunge dive or plunge dive followed by underwater pursuit) and we measured the occurrences and timing of attacks from the different species (mostly Cape gannets and long-beaked common dolphins Delphinus capensis). We also estimated the size of the targeted fish schools. These observations were complemented with a simulation model to evaluate the cumulative effect of successive predator attacks on the prey aggregation structure. The probability to capture a fish in one feeding attempt by Cape gannets averaged 0·28. It was lower when gannets engaged in underwater prey pursuit after the plunge compared to direct plunge (0·13 vs. 0·36). We found no effect of the number of prey on gannets' feeding success. However, the timing and frequency of attacks influenced strongly and positively the feeding success of individuals. The probability to capture a fish was the lowest (0·16) when no attack occurred in the few seconds (1-15 s) prior to a dive and the highest (˜0·4, i.e. more than twice) when one or two attacks occurred during this time window. The simulation model showed that a prey aggregation disorganized just after an attack and that the maximum of disturbance was obtained a few seconds after the initiation of the successive attacks. Our study suggests that, in multispecies predator assemblages, the cumulative effect (through disorganization of school cohesiveness) of the multiple species attacking a prey aggregation may increase the feeding success of each individual. Therefore, facilitation between predators is likely to overcome competition in these multispecific assemblages.
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Affiliation(s)
- Andréa Thiebault
- Institut de Recherche pour le Développement, UMR MARBEC 248: Marine Biodiversity, Exploitation and Conservation, Avenue Jean Monnet CS 30171, 34203, Sète Cedex, France.,Department of Zoology, Nelson Mandela Metropolitan University, South Campus, PO Box 77000, Port Elizabeth, 6031, South Africa
| | - Magali Semeria
- Institut de Recherche pour le Développement, UMR MARBEC 248: Marine Biodiversity, Exploitation and Conservation, Avenue Jean Monnet CS 30171, 34203, Sète Cedex, France.,Institut de Recherche pour le Développement, UMI IRD 209 UPMC UMMISCO, Centre de Recherche Halieutique Méditerranéenne et Tropicale, Avenue Jean Monnet CS 30171, 34203, Sète Cedex, France
| | - Christophe Lett
- Institut de Recherche pour le Développement, UMI IRD 209 UPMC UMMISCO, Centre de Recherche Halieutique Méditerranéenne et Tropicale, Avenue Jean Monnet CS 30171, 34203, Sète Cedex, France
| | - Yann Tremblay
- Institut de Recherche pour le Développement, UMR MARBEC 248: Marine Biodiversity, Exploitation and Conservation, Avenue Jean Monnet CS 30171, 34203, Sète Cedex, France
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27
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Chilvers BL, Morgan KM, Finlayson G, Sievwright KA. Diving behaviour of wildlife impacted by an oil spill: A clean-up and rehabilitation success? MARINE POLLUTION BULLETIN 2015; 100:128-133. [PMID: 26424224 DOI: 10.1016/j.marpolbul.2015.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/10/2015] [Accepted: 09/15/2015] [Indexed: 06/05/2023]
Abstract
The value of rehabilitating oiled wildlife is an on-going global debate. On October 5, 2011, the cargo vessel C/V Rena grounded on Astrolabe Reef, New Zealand (NZ), spilling over 300 tonnes of heavy fuel oil. As part of the Rena oil spill response, 383 little blue penguins (LBP, Eudyptula minor) were captured, cleaned, rehabilitated and released back into a cleaned environment. This research investigates foraging behaviour changes due either to the oil spill or by the rehabilitation process by comparing the diving behaviour of rehabilitated (n=8) and non-rehabilitated (n=6) LBPs and with LBP populations throughout NZ. Stabile isotope analysis of feathers was also used to investigate diet. There were no foraging behaviour differences between rehabilitated and non-rehabilitated LBPs and the overall diving behaviour of these LBPs have similar, if not less energetic, foraging behaviour than other LBPs in NZ. This suggests the rehabilitation process and clean-up undertaken after the Rena appears effective and helps justify the rehabilitation of oiled wildlife across the world.
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Affiliation(s)
- B L Chilvers
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
| | - K M Morgan
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
| | - G Finlayson
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
| | - K A Sievwright
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand
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28
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Collins PM, Green JA, Warwick‐Evans V, Dodd S, Shaw PJA, Arnould JPY, Halsey LG. Interpreting behaviors from accelerometry: a method combining simplicity and objectivity. Ecol Evol 2015; 5:4642-54. [PMID: 26668729 PMCID: PMC4670056 DOI: 10.1002/ece3.1660] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 07/21/2015] [Accepted: 07/22/2015] [Indexed: 11/30/2022] Open
Abstract
Quantifying the behavior of motile, free-ranging animals is difficult. The accelerometry technique offers a method for recording behaviors but interpretation of the data is not straightforward. To date, analysis of such data has either involved subjective, study-specific assignments of behavior to acceleration data or the use of complex analyses based on machine learning. Here, we present a method for automatically classifying acceleration data to represent discrete, coarse-scale behaviors. The method centers on examining the shape of histograms of basic metrics readily derived from acceleration data to objectively determine threshold values by which to separate behaviors. Through application of this method to data collected on two distinct species with greatly differing behavioral repertoires, kittiwakes, and humans, the accuracy of this approach is demonstrated to be very high, comparable to that reported for other automated approaches already published. The method presented offers an alternative to existing methods as it uses biologically grounded arguments to distinguish behaviors, it is objective in determining values by which to separate these behaviors, and it is simple to implement, thus making it potentially widely applicable. The R script coding the method is provided.
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Affiliation(s)
- Philip M. Collins
- School of Life SciencesUniversity of RoehamptonHolybourne AvenueLondonSW15 4JDUnited Kingdom
| | - Jonathan A. Green
- School of Environmental SciencesUniversity of LiverpoolLiverpoolL69 3GPUnited Kingdom
| | | | - Stephen Dodd
- Royal Society for the Protection of BirdsNorth Wales OfficeBangorLL57 4FDUnited Kingdom
| | - Peter J. A. Shaw
- School of Life SciencesUniversity of RoehamptonHolybourne AvenueLondonSW15 4JDUnited Kingdom
| | - John P. Y. Arnould
- School of Life and Environmental SciencesDeakin UniversityMelbourneVictoria3125Australia
| | - Lewis G. Halsey
- School of Life SciencesUniversity of RoehamptonHolybourne AvenueLondonSW15 4JDUnited Kingdom
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29
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Habitat selection in reintroduced giant anteaters: the critical role of conservation areas. J Mammal 2015. [DOI: 10.1093/jmammal/gyv107] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Froy H, Lewis S, Catry P, Bishop CM, Forster IP, Fukuda A, Higuchi H, Phalan B, Xavier JC, Nussey DH, Phillips RA. Age-related variation in foraging behaviour in the wandering albatross at South Georgia: no evidence for senescence. PLoS One 2015; 10:e0116415. [PMID: 25574995 PMCID: PMC4289070 DOI: 10.1371/journal.pone.0116415] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022] Open
Abstract
Age-related variation in demographic rates is now widely documented in wild vertebrate systems, and has significant consequences for population and evolutionary dynamics. However, the mechanisms underpinning such variation, particularly in later life, are less well understood. Foraging efficiency is a key determinant of fitness, with implications for individual life history trade-offs. A variety of faculties known to decline in old age, such as muscular function and visual acuity, are likely to influence foraging performance. We examine age-related variation in the foraging behaviour of a long-lived, wide-ranging oceanic seabird, the wandering albatross Diomedea exulans. Using miniaturised tracking technologies, we compared foraging trip characteristics of birds breeding at Bird Island, South Georgia. Based on movement and immersion data collected during the incubation phase of a single breeding season, and from extensive tracking data collected in previous years from different stages of the breeding cycle, we found limited evidence for age-related variation in commonly reported trip parameters, and failed to detect signs of senescent decline. Our results contrast with the limited number of past studies that have examined foraging behaviour in later life, since these have documented changes in performance consistent with senescence. This highlights the importance of studies across different wild animal populations to gain a broader perspective on the processes driving variation in ageing rates.
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Affiliation(s)
- Hannah Froy
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
- British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
- * E-mail:
| | - Sue Lewis
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Paulo Catry
- Marine and Environmental Sciences Centre, ISPA—Instituto Universitário, Lisbon, Portugal
| | - Charles M. Bishop
- School of Biological Sciences, Bangor University, Bangor, United Kingdom
| | - Isaac P. Forster
- Australian Antarctic Division, University of Tasmania, Kingston, Australia
| | | | | | - Ben Phalan
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Jose C. Xavier
- British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
- Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portuga
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Richard A. Phillips
- British Antarctic Survey, Natural Environment Research Council, Cambridge, United Kingdom
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Salton M, Saraux C, Dann P, Chiaradia A. Carry-over body mass effect from winter to breeding in a resident seabird, the little penguin. ROYAL SOCIETY OPEN SCIENCE 2015. [PMID: 26064587 DOI: 10.1098/rsos.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Using body mass and breeding data of individual penguins collected continuously over 7 years (2002-2008), we examined carry-over effects of winter body mass on timing of laying and breeding success in a resident seabird, the little penguin (Eudyptula minor). The austral winter month of July consistently had the lowest rate of colony attendance, which confirmed our expectation that penguins work hard to find resources at this time between breeding seasons. Contrary to our expectation, body mass in winter (July) was equal or higher than in the period before ('moult-recovery') and after ('pre-breeding') in 5 of 7 years for males and in all 7 years for females. We provided evidence of a carry-over effect of body mass from winter to breeding; females and males with higher body mass in winter were more likely to breed early and males with higher body mass in winter were likely to breed successfully. Sex differences might relate to sex-specific breeding tasks, where females may use their winter reserves to invest in egg-laying, whereas males use their winter reserves to sustain the longer fasts ashore during courtship. Our findings suggest that resident seabirds like little penguins can also benefit from a carry-over effect of winter body mass on subsequent breeding.
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Affiliation(s)
- Marcus Salton
- Research Department , Phillip Island Nature Parks , PO Box 97, Cowes, Victoria 3922, Australia
| | - Claire Saraux
- Institut Pluridisciplinaire Hubert Curien UMR7178 CNRS , 23 Rue Becquerel, 67087 Strasbourg, France ; IFREMER, UMR 212 Exploited Marine Ecosystems , Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France
| | - Peter Dann
- Research Department , Phillip Island Nature Parks , PO Box 97, Cowes, Victoria 3922, Australia
| | - André Chiaradia
- Research Department , Phillip Island Nature Parks , PO Box 97, Cowes, Victoria 3922, Australia
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Salton M, Saraux C, Dann P, Chiaradia A. Carry-over body mass effect from winter to breeding in a resident seabird, the little penguin. ROYAL SOCIETY OPEN SCIENCE 2015; 2:140390. [PMID: 26064587 PMCID: PMC4448785 DOI: 10.1098/rsos.140390] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/22/2014] [Indexed: 06/01/2023]
Abstract
Using body mass and breeding data of individual penguins collected continuously over 7 years (2002-2008), we examined carry-over effects of winter body mass on timing of laying and breeding success in a resident seabird, the little penguin (Eudyptula minor). The austral winter month of July consistently had the lowest rate of colony attendance, which confirmed our expectation that penguins work hard to find resources at this time between breeding seasons. Contrary to our expectation, body mass in winter (July) was equal or higher than in the period before ('moult-recovery') and after ('pre-breeding') in 5 of 7 years for males and in all 7 years for females. We provided evidence of a carry-over effect of body mass from winter to breeding; females and males with higher body mass in winter were more likely to breed early and males with higher body mass in winter were likely to breed successfully. Sex differences might relate to sex-specific breeding tasks, where females may use their winter reserves to invest in egg-laying, whereas males use their winter reserves to sustain the longer fasts ashore during courtship. Our findings suggest that resident seabirds like little penguins can also benefit from a carry-over effect of winter body mass on subsequent breeding.
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Affiliation(s)
- Marcus Salton
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
| | - Claire Saraux
- Institut Pluridisciplinaire Hubert Curien UMR7178 CNRS, 23 Rue Becquerel, 67087 Strasbourg, France
- IFREMER, UMR 212 Exploited Marine Ecosystems, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France
| | - Peter Dann
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
| | - André Chiaradia
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
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Carroll G, Slip D, Jonsen I, Harcourt R. Supervised accelerometry analysis can identify prey capture by penguins at sea. ACTA ACUST UNITED AC 2014; 217:4295-302. [PMID: 25394635 DOI: 10.1242/jeb.113076] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Determining where, when and how much animals eat is fundamental to understanding their ecology. We developed a technique to identify a prey capture signature for little penguins from accelerometry, in order to quantify food intake remotely. We categorised behaviour of captive penguins from HD video and matched this to time-series data from back-mounted accelerometers. We then trained a support vector machine (SVM) to classify the penguins' behaviour at 0.3 s intervals as either 'prey handling' or 'swimming'. We applied this model to accelerometer data collected from foraging wild penguins to identify prey capture events. We compared prey capture and non-prey capture dives to test the model predictions against foraging theory. The SVM had an accuracy of 84.95±0.26% (mean ± s.e.) and a false positive rate of 9.82±0.24% when tested on unseen captive data. For wild data, we defined three independent, consecutive prey handling observations as representing true prey capture, with a false positive rate of 0.09%. Dives with prey captures had longer duration and bottom times, were deeper, had faster ascent rates, and had more 'wiggles' and 'dashes' (proxies for prey encounter used in other studies). The mean (±s.e.) number of prey captures per foraging trip was 446.6±66.28. By recording the behaviour of captive animals on HD video and using a supervised machine learning approach, we show that accelerometry signatures can classify the behaviour of wild animals at unprecedentedly fine scales.
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Affiliation(s)
- Gemma Carroll
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia.
| | - David Slip
- Taronga Conservation Society Australia, Bradley's Head Road, Mosman, Sydney, NSW 2088, Australia
| | - Ian Jonsen
- Taronga Conservation Society Australia, Bradley's Head Road, Mosman, Sydney, NSW 2088, Australia
| | - Rob Harcourt
- Taronga Conservation Society Australia, Bradley's Head Road, Mosman, Sydney, NSW 2088, Australia
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Davison R, Boggs CL, Baudisch A. Resource allocation as a driver of senescence: Life history tradeoffs produce age patterns of mortality. J Theor Biol 2014; 360:251-262. [DOI: 10.1016/j.jtbi.2014.07.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 05/24/2014] [Accepted: 07/10/2014] [Indexed: 11/24/2022]
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Kiere LM, Drummond H. Extrapair behaviour reveals flexible female choosiness and mixed support for classic good genes in blue-footed boobies. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Elliott KH, Hare JF, Le Vaillant M, Gaston AJ, Ropert‐Coudert Y, Anderson WG. Ageing gracefully: physiology but not behaviour declines with age in a diving seabird. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12316] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kyle H. Elliott
- Department of Biological Sciences University of Manitoba Winnipeg Manitoba R3T 2N2 Canada
| | - James F. Hare
- Department of Biological Sciences University of Manitoba Winnipeg Manitoba R3T 2N2 Canada
| | - Maryline Le Vaillant
- IPHC Université de Strasbourg 23 rue Becquerel 67087 Strasbourg France
- Centre National de la Recherche Scientifiques UMR7178 67037 Strasbourg France
| | - Anthony J. Gaston
- National Wildlife Research Centre Environment Canada Carleton University Ottawa OntarioK1A 0H3 Canada
| | - Yan Ropert‐Coudert
- IPHC Université de Strasbourg 23 rue Becquerel 67087 Strasbourg France
- Centre National de la Recherche Scientifiques UMR7178 67037 Strasbourg France
| | - W. Gary Anderson
- Department of Biological Sciences University of Manitoba Winnipeg Manitoba R3T 2N2 Canada
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Darimont CT, Child KR. What enables size-selective trophy hunting of wildlife? PLoS One 2014; 9:e103487. [PMID: 25098246 PMCID: PMC4123890 DOI: 10.1371/journal.pone.0103487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 07/01/2014] [Indexed: 11/19/2022] Open
Abstract
Although rarely considered predators, wildlife hunters can function as important ecological and evolutionary agents. In part, their influence relates to targeting of large reproductive adults within prey populations. Despite known impacts of size-selective harvests, however, we know little about what enables hunters to kill these older, rarer, and presumably more wary individuals. In other mammalian predators, predatory performance varies with knowledge and physical condition, which accumulates and declines, respectively, with age. Moreover, some species evolved camouflage as a physical trait to aid in predatory performance. In this work, we tested whether knowledge-based faculty (use of a hunting guide with accumulated experience in specific areas), physical traits (relative body mass [RBM] and camouflage clothing), and age can predict predatory performance. We measured performance as do many hunters: size of killed cervid prey, using the number of antler tines as a proxy. Examining ∼4300 online photographs of hunters posing with carcasses, we found that only the presence of guides increased the odds of killing larger prey. Accounting for this effect, modest evidence suggested that unguided hunters presumably handicapped with the highest RBM actually had greater odds of killing large prey. There was no association with hunter age, perhaps because of our coarse measure (presence of grey hair) and the performance trade-offs between knowledge accumulation and physical deterioration with age. Despite its prevalence among sampled hunters (80%), camouflage had no influence on size of killed prey. Should these patterns be representative of other areas and prey, and our interpretations correct, evolutionarily-enlightened harvest management might benefit from regulatory scrutiny on guided hunting. More broadly, we suggest that by being nutritionally and demographically de-coupled from prey and aided by efficient killing technology and road access, wildlife hunters in the developed world might have overcome many of the physical, but not knowledge-based, challenges of hunting.
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Affiliation(s)
- Chris T. Darimont
- Department of Geography, University of Victoria, Victoria, BC, Canada
- Raincoast Conservation Foundation, Sidney, BC, Canada
- * E-mail:
| | - K. Rosie Child
- Department of Geography, University of Victoria, Victoria, BC, Canada
- Raincoast Conservation Foundation, Sidney, BC, Canada
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Jaeger A, Goutte A, Lecomte VJ, Richard P, Chastel O, Barbraud C, Weimerskirch H, Cherel Y. Age, sex, and breeding status shape a complex foraging pattern in an extremely long-lived seabird. Ecology 2014; 95:2324-33. [DOI: 10.1890/13-1376.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Fine-scale spatial age segregation in the limited foraging area of an inshore seabird species, the little penguin. Oecologia 2014; 176:399-408. [PMID: 25038901 DOI: 10.1007/s00442-014-3018-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
Competition for food resources can result in spatial and dietary segregation among individuals from the same species. Few studies have looked at such segregations with the combined effect of sex and age in species with short foraging ranges. In this study we examined the 3D spatial use of the environment in a species with a limited foraging area. We equipped 26 little penguins (Eudyptula minor) of known age, sex, and breeding output with GPS (location) and accelerometer (body acceleration and dive depth) loggers. We obtained dietary niche information from the isotopic analysis of blood tissue. We controlled for confounding factors of foraging trip length and food availability by sampling adults at guard stage when parents usually make one-day trips. We observed a spatial segregation between old (>11 years old) and middle-aged penguins (between 5 and 11 years old) in the foraging area. Old penguins foraged closer to the shore, in shallower water. Despite observing age-specific spatial segregation, we found no differences in the diving effort and foraging efficiency between age classes and sexes. Birds appeared to target similar prey types, but showed age-specific variation in their isotopic niche width. We hypothesize that this age-specific segregation was primarily determined by a "cohort effect" that would lead individuals sharing a common life history (i.e. having fledged and dispersed around the same age) to forage preferentially together or to share similar foraging limitations.
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Mata R, Wilke A, Czienskowski U. Foraging across the life span: is there a reduction in exploration with aging? Front Neurosci 2013; 7:53. [PMID: 23616741 PMCID: PMC3627975 DOI: 10.3389/fnins.2013.00053] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 03/20/2013] [Indexed: 11/28/2022] Open
Abstract
Does foraging change across the life span, and in particular, with aging? We report data from two foraging tasks used to investigate age differences in search in external environments as well as internal search in memory. Overall, the evidence suggests that foraging behavior may undergo significant changes across the life span across internal and external search. In particular, we find evidence of a trend toward reduced exploration with increased age. We discuss these findings in light of theories that postulate a link between aging and reductions in novelty seeking and exploratory behavior.
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Affiliation(s)
- Rui Mata
- Center for Adaptive Rationality, Max Planck Institute for Human Development Berlin, Germany
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Pelletier L, Kato A, Chiaradia A, Ropert-Coudert Y. Can thermoclines be a cue to prey distribution for marine top predators? A case study with little penguins. PLoS One 2012; 7:e31768. [PMID: 22536314 PMCID: PMC3335045 DOI: 10.1371/journal.pone.0031768] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 01/18/2012] [Indexed: 11/18/2022] Open
Abstract
The use of top predators as bio-platforms is a modern approach to understanding how physical changes in the environment may influence their foraging success. This study examined if the presence of thermoclines could be a reliable signal of resource availability for a marine top predator, the little penguin (Eudyptula minor). We studied weekly foraging activity of 43 breeding individual penguins equipped with accelerometers. These loggers also recorded water temperature, which we used to detect changes in thermal characteristics of their foraging zone over 5 weeks during the penguin's guard phase. Data showed the thermocline was detected in the first 3 weeks of the study, which coincided with higher foraging efficiency. When a thermocline was not detected in the last two weeks, foraging efficiency decreased as well. We suggest that thermoclines can represent temporary markers of enhanced food availability for this top-predator to which they must optimally adjust their breeding cycle.
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Saraux C, Chiaradia A, Le Maho Y, Ropert-Coudert Y. Everybody needs somebody: unequal parental effort in little penguins. Behav Ecol 2011. [DOI: 10.1093/beheco/arr049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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