28 January 2011

La Nina behind hundreds of little penguin deaths

Little penguins in New Zealand.
Photo by ricklibrarian. Some rights reserved.
NEW ZEALAND - Blame it on the weather. Hundreds of little penguins and other seabirds are starving to death, and conservationists say the La Nina weather pattern may be the reason behind their lack of food.

La Nina is the counterpart of El Nino in the El Nino-Southern Oscillation (ENSO), a climate pattern that occurs across the tropical Pacific Ocean. Although it is a natural phenomenon, ENSO causes extreme weather such as floods and droughts. It is thought that the current La Nina weather pattern - the strongest since 1975 - is responsible for the recent floods in Queensland, Australia.

And for the little penguins, it has meant a lack of prey. MetService weather ambassador Bob McDavitt told The Northern Advocate that La Nina's northerly winds have driven a layer of warm subtropical water on to New Zealand, stopping the usual upwelling of cold, nutrient-rich water around the coast.

In normal conditions, it is these cold currents that stir up the ocean and bring penguin prey such as small fish and plankton near the surface of the water.

Shireen Helps and her husband Francis have been caring for a colony of white-flippered penguins (a subspecies of little penguin) on their Banks Peninsula property for about 25 years. Mrs Helps told The Dominion Post that the unusually warm currents had made it difficult for the adult penguins to find food. They had to stay out foraging at sea for too long, which lead to their chicks starving. Most of the chicks that hatched at the colony between October and December – numbering in the hundreds - had died, she said.

"There were chicks dying in their burrows, in the hillside, and heaps dying on the water."

Department of Conservation vet Kate McInnes told The Northern Advocate the seabird deaths were sad but the result of a natural event. She advised that even if starving birds were rescued, releasing them back into the wild in these lean times was risky.

"Even if we ran around and fed every baby chick we could find, when they fledge they won't be able to find food."

Lisa Argilla, Wellington Zoo’s veterinary science manager, said she was concerned about what would happen to species such as penguins if extreme weather events happened more frequently.

She told The Dominion Post, "They're natural occurrences that always happen, but now they're happening more regularly and it's playing havoc with wildlife populations."

Penguins needed five or six years of good conditions for populations to regenerate, she said.

Scientists are not sure whether ENSO events will be more frequent in the future. But if they are, it could mean little penguin populations are in big trouble.

Sources
Dying birds stir extinction fears by Kiran Chug, 22 January 2011, The Dominion Post

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