Many of our seabirds are nocturnal, petrels in particular. So, as seabird scientists, we’re used to staying up at night to learn more about their lives. We become nocturnal creatures, setting off at dusk to sit in field and forest all night, waiting for them to return from the sea. Coffee keeps us awake for long hours in the dark, staring at the sky.
Awake doesn’t necessarily mean alert though, and after several hours of nothing happening, I am dozing slightly when there’s a small thump and something flies into my leg. I sit up and flick my headlamp on to dull red, and there’s a darker patch of leaf litter next to me. One that is shuffling quietly, bobbing its head from side to side. Through the infra-red camera, it has two glowing orbs for eyes, set in a sloping forehead that tapers down to a delicate bill, a streaky white belly and impossibly long legs.
It’s a New Zealand storm petrel.
These little birds have a miracle story, from rediscovery in 2003 after over 100 years of ‘extinction’ – to the location of their only known breeding site on Te Hauturu-o-Toi, Little Barrier Island in 2013. Now, in the artificial colony of nest-boxes where a speaker system broadcasts their calls at night, I am trying to record their activity. This acoustic attraction system plays recorded New Zealand storm petrel calls on an eight minutes on - eight minutes off cycle all night, imitating the nocturnal chorus that is a thriving petrel colony. It's proven to help establish new colonies in other seabirds - but obviously it's never been tried with New Zealand storm petrels before. It's certainly generating interest. There’s a bird sitting on an egg in one of the nest boxes, and two more have just flown in. Neither of the new arrivals have bands – which is interesting.
Every year, we catch and band New Zealand storm petrels as they return to Hauturu in the evening. That’s what the rest of the team is doing out on the flats, while I’m positioned in the colony. It’s part of our research to get an estimate of the population size. But in our at-sea observations around the Hauraki Gulf, and now here at the artificial colony, most of the birds we see have no bands. So how many New Zealand storm petrels are there? There are at least 490 of them, because that’s the number we’ve banded. But with all these un-banded birds, the good news is that the true population size is likely a quite a bit bigger than that.
It’s a question we can’t answer yet, but every season we get better estimates. Thanks to funding initially from the Dinah Frances Gavin Bequest Fund via the Department of Conservation, and now from the Chisholm-Whitney Family Charitable Trust, we are forming a better picture of the size of the population and learning more about the behavior of these birds. That’s why I’m sitting alone in the dark at the colony with an infra-red camera. Artificial light baffles these small birds, so night-vision is the only way to observe their behaviour without disturbing them. I’m watching and recording as one explores the nest boxes, and then patters around the forest floor, wings held high, fluttering delicately. It's by no means the awkward shuffle of a bird out of it's element - despite being seabirds, storm-petrels are just as at home on the forest floor as they are skimming the waves. For nearly an hour, this tiny dancer skitters around the artificial colony when the speaker system is active. Scampering up the slope, hopping and pirouetting across the forest floor, the white undersides of wing-feathers flashing. During the quiet periods, the little bird folds its wings and scoots back into one of the nest boxes – only to poke an inquisitive head out as soon as the speaker starts up again.
With only one known breeding site (and an unknown population size), the New Zealand storm petrel is listed as Critically Endangered on the IUCN Red List. We also don’t know how the birds are doing from year to year – is the population increasing, decreasing, or steady? We also want to know more about their overall ecology and breeding behaviours. That’s why research like this is so crucial – long-term studies are the only way to answer these questions. And these questions need answering, so that we know where and how to focus our conservation efforts. Every year we learn a little more, but we also learn just how much we don’t know yet.
Early morning – 2am. I’m heading back through the forest out towards the grassy flats, pulled by the chirruping of another speaker broadcasting New Zealand storm petrel calls, and the glow of a floodlight pointed skywards. There are heavy footfalls next to me, and a kiwi appears out of the dark, keeping me company in the forest until I make it out on to the flats. Hauturu is not just a sanctuary for storm-petrels, and many of our native birds, invertebrates, and reptiles thrive in this intact, pest-free ecosystem.
I plant myself on a pillow of long grass, sip a warm concoction of coffee and hot chocolate (which is violently sweet but very welcome), and tilt my neck back to gaze at the sky. After hours alone in a dark forest, it’s nice to watch the stars with the rest of the team. Cook’s petrels soar high through the floodlight, their chattering laughter quiet and distant. Somewhere in the forest behind me, a ruru is hooting, and wētā are scraping. A few hundred metres away, a New Zealand storm petrel is sitting tight on an egg in a nest box, while others investigate the artificial colony around the speaker, dancing in the dark.