Effects of an Arctic Fox Visit to a Low Arctic Seabird Colony

Evidence of sex-specific foraging in monomorphic seabirds is increasing though the underlying mechanisms remain poorly understood. We investigate differential parental care as a mechanism for sex-specific foraging in monomorphic Common Murres (Uria aalge), where the male parent alone provisions the chick after colony departure. Using a combination of geolocation-immersion loggers and stable isotopes, we assess two hypotheses: the reproductive role specialization hypothesis and the energetic constraint hypothesis. We compare the foraging behavior of females (n = 15) and males (n = 9) during bi-parental at the colony, post-fledging male-only parental care and winter when parental care is absent. As predicted by the reproductive role specialization hypothesis, we found evidence of sex-specific foraging during post-fledging only, the stage with the greatest divergence in parental care roles. Single-parenting males spent almost twice as much time diving per day and foraged at lower quality prey patches relative to independent females. This implies a potential energetic constraint for males during the estimated 62.8 ± 8.9 days of offspring dependence at sea. Contrary to the predictions of the energetic constraint hypothesis, we found no evidence of sex-specific foraging during biparental care, suggesting that male parents did not forage for their own benefit before colony departure in anticipation of post-fledging energy constraints. We hypothesize that unpredictable prey conditions at Newfoundland colonies in recent years may limit male parental ability to allocate additional time and energy to self-feeding during biparental care, without compromising chick survival. Our findings support differential parental care as a mechanism for sex-specific foraging in monomorphic murres, and highlight the need to consider ecological context in the interpretation of sex-specific foraging behavior.

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“… A Arctic fox disturbance (details in [ 65 ]) B partial (i.e. < 3 logs) C <10 days UM unsuccessful male (i.e.…”

Section: Resultsmentioning

confidence: 99%

Seasonal Variation in Parental Care Drives Sex-Specific Foraging by a Monomorphic Seabird

2015

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“…We were thus discerning whether individual birds were relatively early or late. Colony departure information on the Gannet Islands was excluded for 2010, when a polar bear Ursus maritimus was present; but was included for Funk Island in 2009 and 2010, when an arctic fox Vulpes lagopus was present at Funk Island [32] , as colony attendance timing there was not detectably affected (LMT unpublished data). As well, despite differences in life history, colony arrival and departure times did not differ detectably between male and female Thick-billed Murres, and differed by only 3 days in Common Murres (LMT unpubl.data).…”

Section: Methodsmentioning

confidence: 99%

Individual Winter Movement Strategies in Two Species of Murre (Uria spp.) in the Northwest Atlantic

et al. 2014

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Individual wintering strategies and patterns of winter site fidelity in successive years are highly variable among seabird species. Yet, an understanding of consistency in timing of movements and the degree of site fidelity is essential for assessing how seabird populations might be influenced by, and respond to, changing conditions on wintering grounds. To explore annual variation in migratory movements and wintering areas, we applied bird-borne geolocators on Thick-billed Murres (Uria lomvia, n = 19) and Common Murres (U. aalge, n = 20) from 5 colonies in the Northwest Atlantic for 2–4 consecutive years. Thick-billed Murres ranged widely and among-individual wintering strategies were highly variable, whereas most Common Murres wintered relatively near their colonies, with among-individual variation represented more by the relative use of inshore vs. offshore habitat. Within individuals, some aspects of the wintering strategy were more repeatable than others: colony arrival and departure dates were more consistent by individual Common than Thick-billed Murres, while the sizes of home ranges (95% utilization distributions) and distances travelled to wintering area were more repeatable for both species. In consecutive years, individual home ranges overlapped from 0–64% (Thick-billed Murres) and 0–95% (Common Murres); and the winter centroids were just 239 km and 169 km apart (respectively). Over the 3–4 year timescale of our study, individuals employed either fixed or flexible wintering strategies; although most birds showed high winter site fidelity, some shifted core ranges after 2 or 3 years. The capacity among seabird species for a combination of fidelity and flexibility, in which individuals may choose from a range of alternative strategies, deserves further, longer term attention.

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“…2005) and may strand polar bears on land, thus necessitating a switch to alternative food sources, such as geese (Stempniewicz 2006). Delayed ice melt enables Arctic foxes to prey on eggs and chicks of island-nesting goose colonies (Tombre et al 1998a,b) and cliff-nesting seabird colonies (Burke et al 2011), drastically reducing the breeding success of these birds. Lack of sea ice in mild winters can further serve to warm adjacent land masses, promoting an early spring melt.…”

Section: Changes In Timing Of Snow and Ice Meltmentioning

confidence: 99%

Warmer Shorter Winters Disrupt Arctic Terrestrial Ecosystems

Cooper

2014

Annu. Rev. Ecol. Evol. Syst.

113

106

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The Earth is warming, especially in polar areas in which winter temperatures and precipitation are expected to increase. Despite a growing research focus on winter climatic change, the impacts on Arctic terrestrial ecosystems remain poorly understood. Snow acts as an insulator, and depth changes affect the enhancement of thermally dependent reactions, such as microbial activity, affecting soil nutrient composition, respiration, and winter gas efflux. Snow depth and spring temperatures influence snowmelt timing, determining the start of plant growth and forage availability. Delays in winter onset affect tundra carbon balance, faunal hibernation, and migration but are unlikely to lengthen the plant growing season. Mild periods in winter followed by a return to freezing have negative consequences for plants and invertebrates, and the resultant ice layers act as barriers to foraging, triggering starvation of herbivores and their predators. In summary, knock-on effects between seasons and trophic levels have important consequences for biological activity, diversity, and ecosystem function.

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Effects of an Arctic Fox Visit to a Low Arctic Seabird Colony

Abstract: Mots clés : renard arctique, Alopex lagopus, changement climatique, Bas-Arctique, tendances caractérisant la glace de mer, guillemots, oiseaux de mer Traduit pour la revue Arctic par Nicole Giguère.

Cited by 10 publications

References 19 publications

Seasonal Variation in Parental Care Drives Sex-Specific Foraging by a Monomorphic Seabird

Seasonal Variation in Parental Care Drives Sex-Specific Foraging by a Monomorphic Seabird

Individual Winter Movement Strategies in Two Species of Murre (Uria spp.) in the Northwest Atlantic

Warmer Shorter Winters Disrupt Arctic Terrestrial Ecosystems

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