Homegrown technology monitors penguin movement
THERE is safety in numbers.
And little penguins group together offshore to form ‘‘rafts’’ of birds when they return to the Oamaru Blue Penguin Colony at night.
But visitors ask a common, confounding question, Oamaru Blue Penguin Colony science and environmental manager Dr Philippa Agnew said, which until now staff had been unable to answer — ‘‘Is it always the same birds that come first?’’
However, since the end of April, Dr Agnew had been using a ‘‘No 8 wire’’ copperwire reconstruction of the microchip readers she used in her PhD work at the colony beginning in 2010 and soon staff could have a much better understanding of individual birds’ behaviour.
The ramp that penguins climb where the landward end of the breakwater meets the penguin colony leads to two corrals, which the penguins enter.
Colony staff would begin to log the number of birds arriving at the colony each night, and could soon know the individual birds that came ashore.
The readers were installed to monitor when microchipped birds were coming and going from the colony, to predict when individuals were more likely to head back out to sea.
Dr Agnew has begun her second year of fitting GPS tracking devices to birds to monitor their prebreeding behaviour at sea and the data will supplement the nightly handcounts of the number of birds which have been made since 1993.
‘‘It’s a really nice way to collect data without actually touching the birds,’’ Dr Agnew said.
‘‘Once you know the ID of the bird, you can find out all the information about it — where it’s breeding, who its partner is, if its partner has come in or they’re home, if they’ve got eggs or chicks.’’
At times, especially now during the prebreeding season, when birds did not have to come and stay ashore, certain parts of the colony would be busy with ‘‘lots of birds ashore’’ while other areas in the colony remained relatively empty.
‘‘They like hanging out together — it might be that they like hanging out together when they raft in. It might be that it’s always the same individuals (rafting in first).
‘‘Sometimes when they’ve been away at sea for a few weeks at a time, a male and a female breeding pair will turn back up in a nesting box on the same day. It does kind of suggest that there’s something . . . coordinated’’
Dr Agnew and the colony staff have microchipped 1129 birds since her PhD work began in 2010 and the number of birds being individually monitored will increase as chicks hatched at the colony are now all being microchipped.
Last year, 163, or 42%, of the colony’s known 386 breeding birds were equipped with microchips.
This prebreeding season study had revealed an exceptionally high number of birds coming ashore nightly, perhaps as a result of a highly productive environment. This indicated a high likelihood of early eggs.
Roughly 200 birds were coming ashore every night at the end of April, when colony staff typically told visitors to expect to see between 20 and 50 birds a night.