Prof John Cockrem

Animals are continuously aware of and responding to their physical and social environment. The key axis that mediates physiological adjustments to changes in the environment is the hypothalamo-pituitary-adrenal (HPA) axis with its hormones cortisol and corticosterone.  These hormones, known as glucocorticoid hormones, have metabolic and behavioural actions that help animals adjust to and cope with short and longer term changes in their environment.  My research programme addresses questions about glucocorticoid responses of animals to environmental stimuli.  Animals are said to experience stress when glucocorticoid secretion increases, so my glucocorticoid research is stress research. 

I am especially interested in the variation between birds in their corticosterone responses.  Individuals consistently have relatively low or high corticosterone responses, with the responses associated with consistent behavioural responses to environmental stimuli known as personalities.  My research investigates relationships between corticosterone responses, personality and fitness (breeding success and the production of offspring) in birds.  This research falls under the broad heading of organismal biology which is the study of structure, function, ecology and evolution at the level of the organism.  Organismal biology is currently experiencing a renaissance, with growing recognition of the importance of studying whole organisms in their environment.

I have worked with Adelie and emperor penguins in Antarctica, and with hoiho (yellow-eyed penguins) and kororā (little penguins) in New Zealand.  The kororā is now my main study species.  The whakataukī (proverb) for my current research programme is "He kororā, he tohu oranga" which means "The little penguin is the sign of life".  The little penguin is the kororā in Māori, and in mātauranga Māori the success of korora populations indicates the health of the coastal environment. 

The overall goals of my research are:

• to understand how individual differences in glucocorticoid stress responses are related to the ability of animals to cope with changes in their environment
• to use knowledge of glucocorticoid stress responses to help predict how populations of animals will respond to climate change
• to use skills in the measurement of stress for the benefit of conservation programmes for free-living and captive animals
• to determine breeding success, body condition, survival and foraging locations of kororā at colonies around the New Zealand coastline and to use these data as indicators of differences between locations and changes from year to year in the health of the marine environment
• to collate and present mātauranga Māori knowledge of the kororā
• to develop novel methods for the establishment of new breeding populations of kororā and hence to reverse the current decline of the species