Measurements of blood progesterone levels during the breeding season of adelie penguins (Pygoscelis adeliae) to determine if foraging trips are synchronised

A late return by either member of a pair can cause nest failure as late returning females may cause the male to abandon the eggs to avoid starvation or if the male is late in returning at the hatching of eggs, the chicks may starve. Pairs synchronise their foraging trip times to avoid these risks.

The possibility of a hormonal level acting as a signal level for returning to the nest was investigated by measuring plasma progesterone levels. Adelie penguins at the Northern rookery, Cape Bird were captured and banded during the courtship/copulation stage. Nests were mapped and monitored on a daily basis to check for the presence of adult birds and date of egg laying.