Dead and alive: Cook’s petrels at Auckland Museum
Last week I stood above an East Coast beach with a Cook’s petrel in hand hoping it was prepared for its flight. As I opened my hands it unfolded its wings. I gently lifted it up and let it go.
Within the last fortnight Auckland Museum has received three wayward Cook’s petrels. One unfortunate bird was found dead in a backyard in Devonport and was donated to the Museum’s research collection. But two others have been found, alive and well, near the Museum’s building needing the help of staff to get back on course.
The pelagic Cook’s petrel (Pterodroma cookii) breeds only in New Zealand and it is currently on the move north. Little Barrier/Hauturu Island (‘resting place of the wind’) in the Hauraki Gulf supports 98% of the world’s population of this little seabird – but many are heading overseas for their first time and their GPS is a little off.
During spring adult Cook’s petrels, weighing in at a mere 200 grams, come together to form pairs and dig burrows of up to three metres under the roots of trees. Around November one white egg is laid and incubated by both parents. After hatching in December a parent will guard the chick for a few days before it is left on its own, to be fed only every 2nd or 3rd night. They were once vulnerable to predation by the Pacific rat or kiore during this time but a successful Department of Conservation programme in 2004 has eradicated kiore from Hauturu, increasing fledging success from 5% to 70%.
At about 90 days the chick fledges and the parents leave, for good. Now on their own full time the chicks spend a few nights exploring and climbing trees searching for take-off sites. Eventually they take flight from mid-March to mid-April, however, some are currently getting a little lost and dazzled by city lights, including the two found near the Museum.
Having retrieved them from the wilds of Auckland Domain the pair were allowed to rest quietly during the day and given meal of fresh terakihi before being released in the evening.
Once the fledglings successfully leave their island homes, or urban Auckland, they will spend the next five years at sea across the eastern and northern Pacific Ocean feeding at night from the surface on squid, crustaceans and fish.
Bird Rescue North Shore releases an average of 15 Cook’s petrels each year that have lost their way into Auckland suburbs. If you happen to find a live petrel you can contact Bird Rescue North Shore, your local Department of Conservation office or me at Auckland Museum for instructions on what to do. It isn’t necessary to take a bird into Bird Rescue unless you believe that it is injured.
Post by: Jason Froggatt
Jason Froggatt trained as a zoologist, has experience working in wildlife conservation and now works as a Collection Manager in Auckland Museum's Natural Sciences team.
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