Opinion: After greater than 100 days at sea, a grey-faced petrel or ōi returns residence with a thud –there’s nothing sleek concerning the touchdown. I’ve heard a number of birds crash-landing within the Pōhutukawa at Te Henga/Bethell’s Seashore in west Auckland because the solar units. A decade in the past, there would extra possible have been silence.
That greater than 150 burrows now exist on the mainland at Te Henga up from solely two in 2014 is testomony to the volunteers who do the laborious yards to take care of traps for rats, stoats, and ferrets. Not all burrows are lively, so I estimate 150 to 200 grownup birds are primarily based on the mainland within the better Te Henga space. The revival alongside the west coast at Te Henga, Cornwallis, Whatipu, Karekare, Piha, and Muriwai is a reminder that Aotearoa’s biodiversity story isn’t nearly loss – typically we quietly achieve again with a little bit can-do angle.
It additionally reveals birds will be restored in inhabited landscapes quite than fenced sanctuaries or offshore islands, which is vital as a result of burrowing seabirds are in worldwide decline. Let me inform you about these exceptional, considerably eccentric, birds. Lengthy-lived – as much as 40 years – and monogamous, ōi return to the identical burrow yearly to lift a single chick. Their burrows, dug with the birds’ ft and highly effective beaks, will be as deep as 2 metres they usually’re musty – the scent jogs my memory of my grandparents’ linen cabinet. Ōi spend most of their lives offshore, foraging over waters greater than a kilometre deep. Deep-sea fishers know the fowl, however on the mainland it’s a special story. Beneath the quilt of darkness, ōi slip in, make a ruckus, and earlier than daybreak they’re gone. Some volunteers setting traps have heard the birds’ distinctive “o-hoe” calls however solely seen an ōi a few times.
For long-term monitoring, the birds are caught and tagged with steel bands on their legs. It’s like holding a pet rooster that has a kitchen knife for a beak. Between 2022 and 2024, for a College of Auckland examine, I monitored greater than 400 burrows throughout 14 colonies on the west coast with my do-it-yourself “burrowscope”, a digital camera and torch strapped to a harakeke department with electrical tape. Investigating burrows, heat air and the musty scent signalled somebody was residence. I paired the monitoring data with knowledge from cameras recording the abundance of Norway rats, ship rats, stoats, cats, possums, and ferrets. This analysis confirmed that suppressing predators – particularly Norway rats and stoats – was most important from August to October when chicks have been youngest. A chick spends most of its time alone, with each dad and mom out foraging, returning periodically with meals. When predators have been stored beneath sure thresholds over this era, the survival charge for chicks was usually greater than 60 p.c, much like predator-free islands and sufficient to take care of or enhance populations. This reveals that predator eradication will not be completely required for seabird restoration; predator suppression can work. The nationwide ōi inhabitants is about 200,000 breeding pairs, virtually all primarily based on the east coast, owing to the extra quite a few islands, lots of that are predator-free. Mainland colonies principally vanished due to predators. Serving to ōi boosts associated ecosystems. Seabirds act as fertilisers for our native coastal vegetation. They forage at sea, consuming fish and squid, and produce these vitamins excessive in nitrogen and phosphorous again onto the land. The guano enriches soils and the birds’ digging turns over the earth. Most of those ecosystem roles as soon as occurred at scale throughout Aotearoa however disappeared when seabirds vanished from the mainland with the introduction of mammalian predators.
We spend quite a lot of time speaking about how dire issues are for native species. I’d love for us to speak extra concerning the birds we’ve saved – and that’s taking place with ōi proper in entrance of us on the west coast. At Te Henga, a small group of devoted volunteers preserve traplines, examine bait stations, fill in funding functions, and get rid of lifeless stoats, rats, and infrequently ferrets. A group group at Cornwallis has adopted the ōi as an emblem, sporting Petrelhead T-shirts and endeavor predator management throughout the Cornwallis peninsula.
Graeme Taylor, from the Division of Conservation, has stored shut watch on the ōi burrows at Te Henga for years. Fellow scientists James Russell and Brendon Dunphy from the College of Auckland and Todd Landers from Auckland Council additionally work to assist ōi within the west.
If you wish to expertise the magic of ōi, exit on a windy autumn evening and hear at headlands close to the coast for the distinctive “o-hoe” calls at nightfall. Or higher but, be a part of a neighborhood group to be a part of the motion and defend a taonga.
