By Ngaire Wallen
The Tawharanui Open Sanctuary is a haven for many species of birds and animals, which provides a perfect opportunity to study the lives of these creatures. Since 2008, students from Canada have come to Tawharanui to study pukeko because of their cooperative breeding patterns. A breeding group of pukeko will have one-to-three breeding males, one-to-three breeding females, and other non-breeding helpers that assist in the care of the nest and chicks. These groups will stay together unless there is another available breeding territory and even if they disperse, new breeding groups will form each year. At Tawharanui, most of the birds are related and because the population numbers are high, the breeding groups stay together. This year, two Masters of Science students, Meghan Healey, who is focussing on territory and population density, and Courtney Young, studying personality and dominance, are busy in the park.
Caught in live capture traps, the birds are banded and blood samples taken for genetic testing. Individual birds can then be identified and their movements and behaviour monitored. Within a nest, eggshell patterns identify groups of eggs. Swabs (the pattern is actually blood from the mother) confirm which eggs are from which bird. It seems researchers can visually identify groups of eggs, but pukeko can’t. The research aims to see if pukeko recognise their own chicks or if the dominant female, who lays first, will preference the older chicks which are more likely to be hers.
When pukeko numbers are culled, and the strict hierarchy of the nest breaks down, the breeding is less successful. No-one is sure how this unusual cooperative breeding came about, nor is there any certainty as to when the pukeko got to New Zealand, but the commonly held thought is that it was sometime between 200 to 400 years ago.
Meghan describes pukeko as “angry, determined birds”. Bruising and peck marks on her hands show this is clearly true. They are also quite smart – the birds have come to recognise both the students and the sound of their vehicle, and quickly head for cover.
The students say there is no identified objective to the study beyond increasing the body of knowledge about the bird. As Courtney points out, “Sometimes the outcomes are not what is expected – hearing aids were developed after the study of hearing in moths and bats.”
At Tawharanui, the predator-free environment has resulted in a boom in pukeko numbers, which is a threat to other species because of their territorial and aggressive behaviour. It is hoped increased knowledge might inform ways to manage the population. There are numerous other research programmes underway at Tawharanui. TOSSI members are often invited to take part in these activities which allow them to get up close and very personal with some of New Zealand’s rarest, and it seems most aggressive, species.
Dateclaimer: The next workday in the park is December 6, starting at 9am at the Woolshed. All welcome.