Mapping the health of Ōi
Our project is based on the assumption that stress causes changes in behaviour and metabolism of seabirds, which may impact breeding success. It stems from research undertaken by University of Auckland researchers 2015-2017 looking at the health of ōi / grey-faced petrel populations in the Auckland region, comparing those breeding on the west coast (Te Henga / Bethells) with those on the east coast (Te Hawere a Maki / Goat Island) close to the mainland. What this study has shown is that ōi on the east coast were not doing as well as those on the west coast, at least during the study period of 3 years.
Working with the School of Biological Sciences, University of Auckland, we are keen to investigate whether this trend holds up for the colonies on islands further offshore – on islands from east Northland through to the Bay of Plenty, which is where 95-98% of the ōi population breed.
To investigate this, endocrine stress hormones laid down in chick feathers between these colonies would be analysed. Feather hormones in chicks record developmental stress, as the hormone is deposited in the feather while it has a blood supply during its growth. What the earlier study showed was that east coast chicks both weighed less and exhibited higher feather stress profiles than those on the west coast, indicating that growing up on the east coast is tougher for these vulnerable life stages.