Survival Analysis of Eggs and Chicks of AdÉlie Penguins (Pygoscelis adeliae)

• Published in: The Auk
• Main Authors: Davis, Lloyd S., McCaffrey, Frances T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 1986
• Subjects: Antarc*; Antarctica; Catharacta maccormicki; Pygoscelis adeliae; South Polar Skuas
• Online Access: http://dx.doi.org/10.1093/auk/103.2.379; http://academic.oup.com/auk/article-pdf/103/2/379/30081041/auk0379.pdf

Abstract Survival analysis was used to examine the fates of eggs in six colonies of Adélie Penguins (Pygoscelis adeliae) at Cape Bird, Antarctica. Hatching success was 56.2% and fledging success for chicks was 63.3%, giving an overall reproductive success of 35.6%. The major cause of losses of both eggs and chicks was predation by South Polar Skuas (Catharacta maccormicki). The second-most important causes of egg and chick mortality were desertion and starvation, respectively, both of which resulted from inadequate timing of nest relief. Eggs were at risk of predation by skuas throughout the incubation period, while chicks were at risk for the first 30 days after hatching. The likelihood of desertion increased after the eggs had been incubated for 16 days and reached a peak at 22-24 days. Starvation occurred during the guard stage and was most likely to occur when chicks were 6-8 days old. Timing of breeding and clutch size were factors that influenced the survival of eggs through the initial stage of incubation. Nest location had a significant effect on the survival of eggs and chicks, from laying through the end of the guard stage. Eggs laid in 2-egg clutches and in central nests were most likely to produce chicks that fledged.