Relationships can be fickle. Sometimes it just doesn’t work, even in penguins that can mate with the same partner for years. The little penguins (Eudyptula small) who live on Phillip Island in Australia appear to ‘separate’ their partners and find a new partner when they seem unhappy with the number of offspring they have produced. However, this is a risky decision that could reduce success in their subsequent breeding attempts. The findings are detailed in a study published Jan. 11 in the journal Ecology and evolution.
Phillip Island is home to the the world’s largest colony of little penguins–almost 40,000 birds. These seabirds are the smallest penguin species on earth. Little penguins are slightly larger than a standard bowling pin, about 30 to 40 centimeters long and weigh about 3 kilos. These birds, also called little blue or fairy penguins, are found in Australia and New Zealand. The colony on Philip Island is home to a popular one Penguin parade that attracts thousands of visitors every year. People can watch them toddling from the ocean to their lairs in the twilight.
This new scientific dive into the love lives of little penguins was conducted for 10 years and 13 breeding seasons. Scientists wanted to determine what little penguin pairs might portend about the colony’s reproductive future. According to Richard Reina, co-author of the study and affiliated with Australia’s Monash University, not all penguins mate for life.
“During good times, they largely stick with their partners, even though a bit of hanky-panky often happens,” Reina said in a statement. “However, after a poor breeding season, they may try to find a new mate for the next season to increase their breeding success.”
During these thirteen breeding seasons, the team kept track of which individuals changed – or divorced – partners from one season to the next.
“During the study, we recorded almost 250 penguin divorces from around a thousand pairs, and we found that years with lower divorce rates resulted in higher breeding success,” Reina said.
The divorce rate among the penguins seems to be a more reliable predictor of reproductive success then environmental factors – such as habitat change – or behavioral traits, including the amount of time they spend searching for prey. More separations and subsequent recouplings in a breeding season result in lower reproductive success throughout the colony.
[ Related: Tiny fossil reveals when penguins evolved their surprisingly useful wings. ]
The team believes that divorce rate was a better predictor of success because it was more accurately correlated with breeding rate than environmental or behavioral factors. Understanding these dynamics can help protect these and other species around Philip Island.
“Our findings on lower divorce rates among little penguins on Phillip Island under favorable environmental conditions highlight the importance of considering social dynamics in addition to environmental factors when designing strategies to protect vulnerable seabird species,” said Andre Chiaradia, co-author of the study and Phillip Island Nature Parks. Marine Scientist, said in a statement.
