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Site fidelity increases reproductive success by increasing foraging efficiency in a marine predator

Citation

Rebstock, Ginger; Abrahms, Briana; Boersma, Dee (2022), Site fidelity increases reproductive success by increasing foraging efficiency in a marine predator, Dryad, Dataset, https://doi.org/10.5061/dryad.8931zcrsv

Abstract

Seabirds must find food efficiently in the dynamic ocean environment to succeed at raising chicks. In theory, site familiarity, gained by prior experience in a place, should increase foraging efficiency when prey is predictable. For non-flying species like penguins, prior experience may be the only source of information on prey location. Penguins should therefore exhibit high foraging-site fidelity, particularly when prey is more predictable. Using movement data from 180 Magellanic penguins Spheniscus magellanicus tracked during 23 years, we measured foraging-site fidelity during the breeding season when penguins make repeated trips from their colony to feed chicks. We tested whether chlorophyll-a concentration, as a proxy for ocean productivity, affects foraging-site fidelity. We then tested whether foraging-site fidelity affects foraging efficiency and reproductive success. Mean foraging-site fidelity was higher in years with higher ocean productivity, when fronts were stronger and prey likely more predictable. When returning to the previously visited foraging site, penguins arrived and returned faster than predicted for the distance, leading to lower mean trip durations and more frequent trips in penguins with high site fidelity. Increased foraging efficiency and chick-feeding frequency in turn led to reduced chick starvation in penguins with high site fidelity. Magellanic penguins use prior experience and foraging-site familiarity to increase reproductive success by increasing foraging efficiency and feeding chicks more frequently. Our study suggests that foraging efficiency is a key mechanism linking foraging-site fidelity and reproductive success. Keywords: Foraging-site fidelity, Site familiarity, Prior experience, Foraging efficiency, Reproductive success, Satellite tracking 

Funding

Wildlife Conservation Society

ExxonMobil Foundation

Pew Charitable Trusts

Disney Worldwide Conservation Fund

National Geographic Society

Lynn Chase Wildlife Foundation

Cunningham Foundation

MKCG Foundation*

Offield Family Foundation

Peach Foundation

Thorne Foundation

Tortuga Foundation

W.K. Kellogg Foundation

Wadsworth Endowed Chair in Conservation Science

Friends of the Penguins