Spring is in the air and Auckland University researchers are watching closely as native pukeko build nests along the Māngere Coastal Walkway.
The breeding site lies close to our Māngere Wastewater Treatment Plant and for the past year, we have enabled staff from the university's School of Biological Sciences to monitor all aspects of the birds' behaviour.
PhD student Aileen Sweeney is one of the team and is focusing on bird dominance within the flock.
Shiny eggs and baby birds provide plenty of scientific material for her thesis: "One of the most interesting things about pukeko is that they are co-operative breeders and joint egg layers. Their nests may contain 10-15 eggs, with unique patterning on them like dots or stripes, which makes my life so much easier because I know with 90 per cent certainty how many different birds have laid eggs in a particular nest."
A pukeko nest at the Māngere Coastal Walkway.
The pukeko are given identification bands - two on each leg. Each bird gets its own unique combination so that they can be easily spotted with binoculars, which is vital because unlike many bird species such as pheasants, male and female pukeko have identical plumage.
Although, the longer Aileen studies the birds, the more she's getting to know their different personalities. Pukeko are known for being intelligent, inquisitive and boisterous and some of the birds are proving to be particularly noisy.
Details such as weight and wing length are recorded, as well as measurements of the 'front shield' or red fleshy cap found above the pukeko's beak. Aileen is exploring the possibility that the size of the shield may relate to dominant behaviour: "I am wondering if bossy, dominate birds have bigger shields. We're taking blood samples to see if hormone levels differ between the various birds too to help prove this theory."
Unfortunately, the pukeko share their home with pests and cats, so chick survival rate is low. Even hatching is a gamble - out of five nests built in the past two months, just one chick has survived but there's no guarantee that a single bird will make it to adulthood.
Environmental technician Liam Templeton organises pest control programmes alongside staff from Ambury Park: "It's a constant battle. More than 10,000 birds, some of them quite endangered, visit the Coastal Walkway each season and we try to protect them from predators as much as we can, with rat and stoat traps, etc.
"Even large birds like swans have their nests attacked. It's quite heart-breaking to see when you think of all the effort that goes into building and laying a nest."
The Coastal Walkway is popular with walkers and cyclists and visitors are asked to be careful not to disturb nesting birds.
Aileen is due to complete her study in two years' time.