Anchovy key to penguins' success

The little penguins ?who call the St Kilda breakwater home love their anchovies. The oily fish is their meal of choice, ?accounting for up to 78 per cent of their diet.

But research has shown that if the bay's anchovy numbers fall and alternative food sources are not available, the impact on the penguin's reproductive success rate could be dramatic.

Monash University ecologist Nicole Kowalczyk said GPS tracking of the birds revealed little penguins had a limited foraging range in the bay, travelling between 10 and 20 kilometres to feed. If, during the breeding season, adults had to travel further to find food, their chicks paid the price. Greater distances meant parents made fewer trips back to shore and delivered fewer meals to their offspring.

"It's shows how important it is that there is a local supply of food," Ms Kowalczyk said. "In the past the penguins have been over-reliant on anchovies and that has been associated with low reproductive success, not just at the St Kilda colony but at other sites around the bay."

When the drought ended in 2010 and stormwater and run-off entered the bay, anchovy availability fell. Alternative food sources for penguins such as pilchards, bay squid and southern garfish were also low.

More time away from home due to longer foraging trips meant that adult penguins struggled to incubate their eggs or feed their chicks, leading to nests and chicks being abandoned.

The research, a collaboration between Monash University and Phillip Island Nature Parks, is published in the journal Functional Ecology on Thursday.

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