Haematocrit values in chinstrap penguins (Pygoscelis antarctica): Variation with age and reproductive status

We studied haematocrit variation with age and reproductive status in chinstrap penguins (Pygoscelis antarctica) at Deception Island, South Shetlands. There was a significant difference in haematocrit values between different age groups (adults vs nestlings and juveniles). Adults had a higher haematocrit value than juveniles and nestlings and juveniles had higher haematocrit values than nestlings. There was also a significant difference in haematocrit values between adults of different status (breeding vs moulting). Breeding adults had higher haematocrit values than moulting adults. The observed differences between age groups were thought to be the result of different oxygen demands due to exercise. The observed differences between adults of different status could reflect the different demands associated with reproduction and moult fasting.