11 September 2011

Little penguins take break from parenting duties

AUSTRALIA - A joint study between Australian and French scientists, to be published in Ecology, has discovered a sophisticated feeding strategy for little penguins, enabling them to take regular breaks from raising their chicks.

“We found little penguins alternate between two consecutive long trips and several short foraging trips while rearing their offspring,” said Claire Saraux, a French student from the University of Strasbourg conducting her PhD project in Australia.

“That strategy is almost never observed in inshore marine birds that forage close to land.”

Life history theory predicts long-lived species such as penguins favour their own survival over breeding and the survival of their offspring. Little penguins, however, have developed a fine foraging plan that balances the demands of chick rearing and parental survival.

“Short foraging trips yield larger meals and allow for regular provisioning of chicks.

But adults can deplete their energy reserves during these trips and ultimately risk their own survival,” Ms Saraux said.

To improve their body condition, breeding adults switch to longer foraging trips when they reach a low threshold mass.

“The two consecutive long trips therefore enable little penguin parents to rebuild their reserves before another round of short trips.”

Dr André Chiaradia, joint author and penguin biologist with Phillip Island Nature Parks, noted researchers previously thought little penguins making longer foraging trips were struggling to feed their chicks, or had abandoned them altogether.

“Food can be patchy where little penguins forage. But this pattern of alternating short and long trips is repeated every year, regardless whether the feeding conditions are good or bad,” he said.

“Finding foraging patterns in animals is crucial, as it contributes to us understanding how animals are resilient to changes in their environment,” Dr Chiaradia concluded.

The study was conducted using eight years of data. The data was collected with the aid of an automatic penguin weigh bridge located on a penguin pathway at Phillip Island's Penguin Parade.

Little penguins take a break from raising their offspring, 18 August 2011, Phillip Island Nature Parks

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