Baseline Corticosterone Peaks in Shorebirds with Maximal Energy Stores for Migration: A General Preparatory Mechanism for Rapid Behavioral and Metabolic Transitions?

From Pubwiki

[edit] Author(s)

• Piersma, T.
• Reneerkens, J.
• Ramenofsky, M.

[edit] Journal

General and Comparative Endocrinology 120.1 (2000): 118-26.

[edit] Keywords

corticosterone environmental unpredictability migration shorebirds stress knots calidris-canutus zonotrichia leucophrys gambelii passerine birds plasma-corticosterone sylvia-borin distance dispersal sparrows migrant flight

[edit] Abstract

In captive red knots (Calidris canutus, Scolopacidae) showing a regulated body mass increase of 50% related to their migration from temperate staging sites to tundra:breeding grounds, plasma corticosterone concentrations increased from less than 10 ng.ml(-1) to levels as high-as 30 ng.ml(-1) when the energy storage for migration was complete. These birds did not fly, but concentrations dropped to very low levels (<5 ng.ml(-1)) as soon as the birds started their voluntary fasts to the low body masses preceding the early wing and body molts normally occurring after an unsuccessful breeding season. As the elevated levels of corticosterone are associated with stable body mass rather than with the preceding increase or subsequent decrease, it is suggested that a major role of corticosterone during the final stages just before departure may be to prepare birds for long-distance flights. Birds heading into the Arctic to breed face potentially arduous flights into unpredictable environmental and social conditions. Activation of the hypothalamic-pituitary-adrenal axis, as measured by elevated levels of corticosterone, may induce the suite of behavioral and metabolic changes necessary to negotiate these challenges successfully. (C) 2000 Academic Press.

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