Unwrapping an Enigma
Little Barrier Island is one of those magical places where time feels as if it stands still and birds, so rare elsewhere, abound. Kokako and saddleback are just part of the everyday soundscape and bellbirds are so common that their song is a constant companion not just an occasional delightful toll. Huge kauri and hard beech trees rise into the mist on this rugged volcanic island.
I have come here to join the New Zealand storm petrel team for a week, building on last year’s huge success of finding them breeding on the island. NZ stormies were thought to be extinct until rediscovered in 2003. Nests were found last autumn in a deep valley amongst beech and kauri trees.
Now we want to know how big the population is and how widespread – are they just confined to a single valley or in other areas, and how did they survive there and nowhere else? Is the population now safe from extinction or teetering on the brink?
On my first night I found myself lying in the grass on the flats along from the Ranger station watching the sky. Using spotlights our task was to spot any NZ stormies flying through and then attempt to ‘land’ them. The team had already had success with this method the previous week and more than 20 birds had been caught and banded and tiny radio transmitters attached to the tails of 7 birds in breeding condition, with the hope they would lead us to more nests. Just 4 nests are known and one nest has a bird sitting on her egg – the very first ever NZSP egg to be found.
To monitor and capture the birds a suite of equipment was deployed, including remote nest cameras to show the birds comings and goings. We also set up a mist net and speakers playing recordings we had retrieved from the automatic recorders which we thought might be NZ stormies. Now that all the lures were in place, we just needed to wait for the birds to fly in from the sea.
I heard kiwis snuffling and scratching in the litter under trees nearby and the occasional screech of a long-tailed cuckoo pierced the night. The stars were mesmerising and shone brightly, undimmed by air pollution or city light bleed. Cooks petrels – silhouetted by our beam – flew in from the sea, to feed their hungry chicks , then a little while later we saw them heading back out again in search of more food for their hungry chicks.
I wandered along to check the net and and to my great excitement there was a NZ stormie there! After we untangled him and bought him along to the tarpaulin for processing where we took blood samples, fitted him with the transmitter and banded him so he could be spotted at sea. Later on the same night we also found another bird near to the speaker, but not in the net. This was a strong indication that the calls we had were indeed those of a NZ stormie.
Holding one of these tiny birds in my hand I marveled that they are so light, just 34 grams or so ( the equivalent weight of three $2 coins). They seem so delicate with their stick thin legs and tiny beak. It is amazing to think they live happily out at sea, only coming in to land to breed. It seems so strange to have two such remarkably different habitats to live in – one a vast featureless ocean and the other an ancient kauri forest full of terrestrial creatures.
Later on a morepork seemed to be taking too much interest in the moths flying into the light and we worried that we might be putting the NZ stormies at risk of a deadly encounter with one, so we shut down for the night. It’s highly likely that morepork are a natural predator of NZ stormies so precaution prevailed.
Daytime saw us hiking the hills and valleys trying to pick up signals from the transmitters we had placed on the birds, but as yet to no avail. Our time on the island comes to an end soon but people will be back periodically during the breeding season to check on the progress of the egg and nest and to retrieve information from the automatic cameras and recorders…and hopefully to find some more nesting sites.
Note: This research mission was partly funded by our Auckland Central and Mid North branches as well as the little Barrier Island (Hauturu) Supporters Trust.