Annual variations in plasma retinol and alpha-tocopherol levels in gentoo and rockhopper penguins

Abstract 10.1002/zoo.1430120507.abs Blood samples were taken throughout the year from captive gentoo Pygoscelis papua (n = 5) and rockhopper Eudyptes crestatus (n = 10) penguins to measure seasonal variations in retinol and alpha-tocopherol levels. Retinol levels ranged from .58 μg/ml to 1.09 μg/ml and alpha-tocopherol levels from 30.8 μg/ml to 50.7 μg/ml for the gentoo […]

Individual breeding decisions and long-term reproductive strategy in the King Penguin Aptenodytes patagonicus

Although studied for 35 years, knowledge of the reproductive biology of the King Penguin Aptenodytes patagonicus remains incomplete. The chick requires more than 12 months of care, which extends the breeding cycle, including moult, to more than one year, i.e. the King Penguin is neither annual nor biennial. In an attempt to resolve ambiguities in […]

Lack of seasonal and moult-related stress modulation in an opportunistically breeding bird: The white-plumed honeyeater (Lichenostomus penicillatus)

This article is part of a Special Issue “SBN 2014”. In most vertebrate species, glucocorticoid levels and stress sensitivity vary in relation to season and life-history stage. In birds, baseline corticosterone (CORT) and stress sensitivity are typically highest while breeding and decrease substantially during moult. Because elevated CORT adversely affects protein synthesis, moult-related CORT suppression […]