Fat daddy's best - for penguins

Size definitely matters when female penguins choose a mate. Photo / Paul Estcourt

When it comes to finding the perfect partner, female penguins are looking for the fattest male with the best voice and great nest-making skills - traits that indicate he'll be a great dad who isn't going to up and leave.

And, according to an Auckland researcher there's no way of faking it either.

Penguins who try to bluff their potential partners by puffing out their features to appear bigger are likely to be caught out.

Auckland University student Emma Marks spent three months in Antarctica's remote Ross Island studying the courtship calls of Adelie penguins, which come on land for just a few short months each summer to breed and raise their chicks - a task mastered by "tag-team parenting".

Dr Marks said males arrive first to find the best spot and build a nest, which more experienced penguins are much better at than first time expectant fathers.

When the females arrive, the males serenade prospective mates by throwing their heads back, pointing their beaks to the sky, and emitting a series of hoarse trills and squawks.

"They're not musical calls - they sound like a cross between a donkey and a stalled car," said Dr Marks.

While the calls are far from romantic, they hold clues for the females as to what kind of dad the male will be - something that is important because it's the male who spends the first two weeks sitting on the eggs without a chance to break for something to eat.