Posted on 21/01/2015 by Phillip Island Nature Parks

Podgy penguins make better breeders

Putting on a little weight over winter increases a penguin’s sexual success according to new research published today in Royal Society Open Science.    

Researchers at Phillip Island, Australia, in collaboration with scientists from the French Research Council, discovered the winter body mass of little penguins has a carry-over effect on timing of breeding and reproductive success during spring and summer.

“Little penguin parents that put on weight in winter, and were heavier than their mass before or after July, were more likely to lay their eggs early, and males were more likely to successfully breed,” Dr André Chiaradia, research scientist at Phillip Island Nature Parks, said.

The research team discovered that females invest their extra winter weight in egg laying, whereas males use their winter reserves to increase their chance of sustaining body condition throughout longer periods ashore during courtship. 

The body mass gains and early egg laying also have the advantage of allowing little penguins to make multiple breeding attempts across the season in years of good food availability, or feed chicks longer in the event that conditions deteriorate during the breeding season.

For Dr Chiaradia the research is proof that size really matters in the penguin colony: “Acquiring and maintaining a good body condition in the lead up to breeding is an effective strategy to meeting the energy demands associated with finding a partner and raising chicks.”