MEPS 593:261-274 (2018)  -  DOI: https://doi.org/10.3354/meps12509

ABSTRACT: The largest breeding population of red-legged kittiwakes Rissa brevirostris has undergone a dramatic decline and subsequent recovery since 1975. The causal mechanism is hypothesized to be climate-induced food shortages during reproduction, yet little is known about how the basin ecosystem, where breeding red-legged kittiwakes primarily forage, is affected by climate variability. We examined when and under what conditions red-legged kittiwakes experienced food shortages. Head feathers (winter) and first primary feathers (summer; n = 24 and 27 yr, and 194 and 122 individuals, respectively) were collected between 1913 and 2016 on St. George Island and were analyzed for stable isotope signatures of carbon (δ¹³C), nitrogen (δ¹⁵N), and sulfur (δ³⁴S). Feathers were also analyzed for corticosterone concentration (fCORT), which indicates a bird’s exposure to nutritional stress during feather growth. Summer fCORT concentrations were lower when values of the annual Pacific Decadal Oscillation index were positive. Winter fCORT concentrations and δ¹⁵N signatures increased when February sea-ice coverage was extensive. We conclude that, since 1913, warm conditions in the Bering Sea ecosystem have been associated with low nutritional stress in adult red-legged kittiwakes breeding on St. George Island. However, we found no strong evidence for isotopic shifts over this same period. A better understanding of the factors governing the abundance and availability of red-legged kittiwakes’ prey is needed to predict the impact of anticipated warming on this species and its foraging habitat.

KEY WORDS:  Historical ecophysiology · Feather corticosterone · St. George Island · Stable isotope analysis · Food shortage · Nutritional stress.

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Cite this article as: Will AP, Kitaiskaia EV, Kitaysky AS (2018) Red-legged kittiwake feathers link food availability to environmental changes in the Bering Sea. Mar Ecol Prog Ser 593:261-274. https://doi.org/10.3354/meps12509 Export citation Share:    Facebook - - linkedIn