Serenades Help Female Penguins Identify the Right Mate
14.07.2010 - Flora & Fauna, Antarctic
Every summer, when the time comes to breed and raise their chicks, Antarctic penguins gather on land. Males arrive first to claim their territory and build a nest, and when females arrive, males try to seduce them through what is better known as the Ecstatic Display Call (EDC). According to Emma Marks from the University of Auckland, the serenade contains inmportant information for female penguins. In a study, published in the journal Behaviour, Marks and her colleagues suggest that besides its role in territorial defense, the EDC helps penguin females predict body condition and possibly breeding success.
When the penguin female heads back to sea after laying two eggs, the role played by the male penguin becomes crucial as he will be the one to look after the eggs until the female returns to take over. During this period, male penguins fast, relying on their accumulated fat to take care of the egg non-stop.
In order to find out how the EDC helped the penguin females make their choice, the team set up camp on Ross Island in Antarctica, where they weighed dozens of penguins over three months, recorded their EDC with a microphone, and noted the individuals’ breeding success. After examining the various calls, the researchers found that a steady frequency over the longest part of the call best predicts a male’s breeding success. The males with the most consistent pitch were apparently the heaviest and the most successful at raising chicks. The sound of the EDC, the team found, is determined by the fat that surrounds a male’s voice box, which allows penguin females to tell how fat males are and thus determine how likely they are to leave the nest and desert their chicks.
