ABSTRACT
Understanding the environmental and behavioral factors that influence how organisms maintain energy balance can inform us about their potential resiliency to rapid environmental changes. Flexibility in maintaining energy balance is particularly important to long-lived, central-place foraging seabirds that are constrained when locating food for offspring in a dynamic ocean environment. To understand the role of environmental interactions, behavioral flexibility and morphological constraints on energy balance, we used doubly labeled water to measure the at-sea daily energy expenditure (DEE) of two sympatrically breeding seabirds, Campbell (Thalassarche impavida) and grey-headed (Thalassarche chrysostoma) albatrosses. We found that species and sexes had similar foraging costs, but DEE varied between years for both species and sexes during early chick rearing in two consecutive seasons. For both species, greater DEE was positively associated with larger proportional mass gain, lower mean wind speeds during water take-offs, greater proportions of strong tailwinds (>12 m s−1), and younger chick age. Greater proportional mass gains were marginally more costly in male albatrosses that already have higher wing loading. DEE was higher during flights with a greater proportion of strong headwinds for grey-headed albatrosses only. Poleward winds are forecasted to intensify over the next century, which may increase DEE for grey-headed albatrosses that heavily use this region during early chick rearing. Female Campbell albatrosses may be negatively affected by forecasted slackening winds at lower latitudes due to an expected greater reliance on less energy efficient sit-and-wait foraging strategies. Behavioral plasticity associated with environmental variation may influence future population responses to climate change of both species.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: C.E.K., D.E.C., D.P.C., S.A.S.; Methodology: C.E.K.; Formal analysis: C.E.K., D.E.C., S.A.S.; Investigation: C.E.K., D.E.C., R.A.O., P.M.S., L.A.S., T.A.; Resources: D.E.C., D.R.T., L.G.T., P.M.S., L.A.S., T.A., S.A.S.; Writing - original draft: C.E.K.; Writing - review & editing: D.E.C., R.A.O., D.R.T., L.G.T., P.M.S., L.A.S., D.P.C., S.A.S.; Visualization: C.E.K.; Supervision: S.A.S.; Project administration: D.R.T., L.G.T.; Funding acquisition: D.R.T., L.G.T., P.M.S.
Funding
This work was supported by the New Zealand Ministry of Business, Innovation and Employment (contract CO1X0905); MARES program (grant FPA 2011-0016); American Ornithologists’ Union; Earl H. and Ethel M. Myers Oceanographic and Marine Biology Trust; Jim Brown Award; San José State University Graduate Student Research Award; and crowd-source funding from Experiment.com (individual donors: Jeff Pentel, Wayne Sentman, Jill Marketos Milburn, Laura Wagner, Mark Kroeger, David Thompson, Sadie Birdfeather, Jen Jelincic, Amy Lush, Paul Richard Wagner, Lucius Bono, Scott Shaffer, Beth Flint, Anita Phagan, Cassie Marketos, Anne Cassell, Dan Saltman, Sandra Machado, Herma Van Gerner, Annie Schmidt, Renee Murphy Shaffer, Heather Day, Corey Clatterbuck, Emily Nichols, Susy Alarcon Arriaga, Cleo Small, Devon O'Meara, Mary Moskal, Wynter Skye Standish, Rachael Orben, Hannah Madden, Oscar Jasklowski and Cindy Wu).
Supplementary information
Supplementary information available online at https://jeb.biologists.org/lookup/doi/10.1242/jeb.228585.supplemental
- Received May 10, 2020.
- Accepted October 12, 2020.
- © 2020. Published by The Company of Biologists Ltd
Log in using your username and password
Log in through your institution
Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$30.00 .
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.