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Hanssen SA, Erikstad KE, Sandvik H, Tveraa T, Bustnes JO. Eyes on the future: buffering increased costs of incubation by abandoning offspring. Behav Ecol 2022. [DOI: 10.1093/beheco/arac116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Abstract
Life history theory states that the resources invested in current reproduction must be traded off against resources needed for survival and future reproduction. Long-lived organisms have a higher residual reproductive value and are therefore expected to be sensitive to reproductive investments that may reduce survival and future reproduction. Individuals within a population may vary in phenotypic quality, experience, access to resources etc. This may affect their optimal reproductive investment level. In this study we manipulated reproductive costs by shortening and extending the incubation period in common eiders Somateria mollissima without altering clutch size. Females whose incubation time was prolonged experimentally, suffered higher mass loss and increased clutch loss/nest desertion. These females were also more prone to abandon their brood after hatching. Both clutch loss and brood abandonment decreased with clutch size in all treatment categories, indicating higher phenotypic quality and/or better access to resources for females producing more eggs. However, although females with prolonged incubation were lighter at hatching, their return rate and breeding performance in the following year were unaffected. These results show that individual quality as expressed through clutch size and body mass is affecting current reproductive investment level as well as future survival and breeding performance. The results also show that individual birds are sensitive to changes in their own condition, and when reproductive effort is approaching a level where survival or future survival may be compromised, they respond by terminating their current reproductive attempt.
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Affiliation(s)
- Sveinn Are Hanssen
- Norwegian Institute of Nature Research, Dept. of Arctic Ecology, FRAM – High North Research Centre for Climate and the Environment , P.O. Box 6606 Langnes, NO-9296 Tromsø , Norway
| | - Kjell Einar Erikstad
- Norwegian Institute of Nature Research, Dept. of Arctic Ecology, FRAM – High North Research Centre for Climate and the Environment , P.O. Box 6606 Langnes, NO-9296 Tromsø , Norway
| | - Hanno Sandvik
- Norwegian Institute of Nature Research, Dept. of Aquatic Biodiversity , P.O. Box 5685 Torgarden, NO-7485 Trondheim , Norway
- Centre of Biodiversity Dynamics, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Torkild Tveraa
- Norwegian Institute of Nature Research, Dept. of Arctic Ecology, FRAM – High North Research Centre for Climate and the Environment , P.O. Box 6606 Langnes, NO-9296 Tromsø , Norway
| | - Jan Ove Bustnes
- Norwegian Institute of Nature Research, Dept. of Arctic Ecology, FRAM – High North Research Centre for Climate and the Environment , P.O. Box 6606 Langnes, NO-9296 Tromsø , Norway
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Öst M, Lehikoinen A, Jaatinen K. Top–down effects override climate forcing on reproductive success in a declining sea duck. OIKOS 2021. [DOI: 10.1111/oik.08762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Markus Öst
- Environmental and Marine Biology, Biocity, Åbo Akademi Univ. Turku Finland
- Novia Univ. of Applied Sciences Ekenäs Finland
| | - Aleksi Lehikoinen
- Finnish Museum of Natural History, Univ. of Helsinki Helsinki Finland
| | - Kim Jaatinen
- Nature and Game Management Trust Finland Degerby Finland
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Jagielski PM, Dey CJ, Gilchrist HG, Richardson ES, Love OP, Semeniuk CAD. Polar bears are inefficient predators of seabird eggs. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210391. [PMID: 33868701 PMCID: PMC8025307 DOI: 10.1098/rsos.210391] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Climate-mediated sea-ice loss is disrupting the foraging ecology of polar bears (Ursus maritimus) across much of their range. As a result, there have been increased reports of polar bears foraging on seabird eggs across parts of their range. Given that polar bears have evolved to hunt seals on ice, they may not be efficient predators of seabird eggs. We investigated polar bears' foraging performance on common eider (Somateria mollissima) eggs on Mitivik Island, Nunavut, Canada to test whether bear decision-making heuristics are consistent with expectations of optimal foraging theory. Using aerial-drones, we recorded multiple foraging bouts over 11 days, and found that as clutches were depleted to completion, bears did not exhibit foraging behaviours matched to resource density. As the season progressed, bears visited fewer nests overall, but marginally increased their visitation to nests that were already empty. Bears did not display different movement modes related to nest density, but became less selective in their choice of clutches to consume. Lastly, bears that capitalized on visual cues of flushing eider hens significantly increased the number of clutches they consumed; however, they did not use this strategy consistently or universally. The foraging behaviours exhibited by polar bears in this study suggest they are inefficient predators of seabird eggs, particularly in the context of matching behaviours to resource density.
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Affiliation(s)
- Patrick M. Jagielski
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON Canada, N9B 3P4
| | - Cody J. Dey
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON Canada, N9B 3P4
| | - H. Grant Gilchrist
- Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON Canada
| | - Evan S. Richardson
- Science and Technology Branch, Environment and Climate Change Canada, Winnipeg, MB Canada
| | - Oliver P. Love
- Department of Integrative Biology, University of Windsor, Windsor, ON Canada
| | - Christina A. D. Semeniuk
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON Canada, N9B 3P4
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Jagielski PM, Dey CJ, Gilchrist HG, Richardson ES, Semeniuk CA. Polar bear foraging on common eider eggs: estimating the energetic consequences of a climate-mediated behavioural shift. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2020.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Bravo C, Pays O, Sarasa M, Bretagnolle V. Revisiting an old question: Which predators eat eggs of ground-nesting birds in farmland landscapes? THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 744:140895. [PMID: 32721676 DOI: 10.1016/j.scitotenv.2020.140895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/09/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Nest predation is a major cause of reproductive failure in birds, but predator identity often remains unknown. Additionally, although corvids are considered major nest predators in farmland landscapes, whether breeders or floaters are involved remains contentious. In this study, we aimed to identify nest predators using artificial nests, and test whether territorial or non-breeders carrion crow (Corvus corone) and Eurasian magpie (Pica pica) were most likely involved. We set up an experiment with artificial ground nests (n = 1429) in farmland landscapes of western France, and assessed how different combinations of egg size and egg material (small plasticine egg, large plasticine egg, quail and natural hen eggs) might influence predation rates and predator species involved. Nest predators were identified using remotely triggered cameras and marks left in plasticine eggs. Corvids were by far the predators most involved (almost 80% of all predation events), independent of egg type. Carrion crows alone were involved in 60% of cases. Probability of predation increased with egg size, and predation rate was higher for natural than for artificial eggs, suggesting that, in addition to egg size, predators might perceive plasticine and natural eggs differently. Predation rates of artificial nests by corvids were related significantly to corvid abundance, and far more to breeder than floater abundances, for both carrion crows and magpies. This study emphasizes the importance of identifying predators at species level, and considering their social status when assessing corvid abundance impact on prey population dynamics. Combining camera traps and plasticine eggs can achieve this objective. Given the high predation rate by carrion crows, a better understanding of landscape-mediated changes in predator diet seems mandatory to design mitigation schemes able to confront ecological challenges raised by generalist predators.
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Affiliation(s)
- Carolina Bravo
- Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and La Rochelle Université, F-79360 Beauvoir-sur- Niort, France; LETG-Angers, UMR 6554, CNRS, Université d'Angers, 49045 Angers, France.
| | - Olivier Pays
- LETG-Angers, UMR 6554, CNRS, Université d'Angers, 49045 Angers, France; REHABS International Research Laboratory, CNRS-Université Lyon 1-Nelson Mandela University, George Campus, Madiba drive, 6531 George, South Africa
| | - Mathieu Sarasa
- BEOPS, 1 Esplanade Compans Caffarelli, 31000 Toulouse, France; Fédération Nationale des Chasseurs, 92136 Issy-les-Moulineaux cedex, France
| | - Vincent Bretagnolle
- Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and La Rochelle Université, F-79360 Beauvoir-sur- Niort, France; LTSER "Zone Atelier Plaine & Val de Sèvre", CNRS, 79360 Villiers-en-Bois, France
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Bårdsen BJ, Hanssen SA, Bustnes JO. Multiple stressors: modeling the effect of pollution, climate, and predation on viability of a sub-arctic marine bird. Ecosphere 2018. [DOI: 10.1002/ecs2.2342] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Bård-Jørgen Bårdsen
- Arctic Ecology Department; Fram Centre; Norwegian Institute for Nature Research (NINA); N-9296 Tromsø Norway
| | - Sveinn Are Hanssen
- Arctic Ecology Department; Fram Centre; Norwegian Institute for Nature Research (NINA); N-9296 Tromsø Norway
| | - Jan Ove Bustnes
- Arctic Ecology Department; Fram Centre; Norwegian Institute for Nature Research (NINA); N-9296 Tromsø Norway
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Informed renesting decisions: the effect of nest predation risk. Oecologia 2013; 174:1159-67. [DOI: 10.1007/s00442-013-2847-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 11/18/2013] [Indexed: 10/26/2022]
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Hanssen SA, Moe B, Bårdsen BJ, Hanssen F, Gabrielsen GW. A natural antipredation experiment: predator control and reduced sea ice increases colony size in a long-lived duck. Ecol Evol 2013; 3:3554-64. [PMID: 24223290 PMCID: PMC3797499 DOI: 10.1002/ece3.735] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 12/02/2022] Open
Abstract
Anthropogenic impact on the environment and wildlife are multifaceted and far-reaching. On a smaller scale, controlling for predators has been increasing the yield from local natural prey resources. Globally, human-induced global warming is expected to impose severe negative effects on ecosystems, an effect that is expected to be even more pronounced in the scarcely populated northern latitudes. The clearest indication of a changing Arctic climate is an increase in both air and ocean temperatures leading to reduced sea ice distribution. Population viability is for long-lived species dependent on adult survival and recruitment. Predation is the main mortality cause in many bird populations, and egg predation is considered the main cause of reproductive failure in many birds. To assess the effect of predation and climate, we compared population time series from a natural experiment where a trapper/down collector has been licensed to actively protect breeding common eiders Somateria mollissima (a large seaduck) by shooting/chasing egg predators, with time series from another eider colony located within a nature reserve with no manipulation of egg predators. We found that actively limiting predator activity led to an increase in the population growth rate and carrying capacity with a factor of 3-4 compared to that found in the control population. We also found that population numbers were higher in years with reduced concentration of spring sea ice. We conclude that there was a large positive impact of human limitation of egg predators, and that this lead to higher population growth rate and a large increase in size of the breeding colony. We also report a positive effect of warming climate in the high arctic as reduced sea-ice concentrations was associated with higher numbers of breeding birds.
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Affiliation(s)
- Sveinn A Hanssen
- Arctic Ecology Department, Norwegian Institute for Nature Research, Fram Centre N-9296, Tromsø, Norway
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