Shorebirds More Likely to Divorce After Successful Mating

Often the female is the one to leave the chicks behind.

Piping Plover with chicks
One plover will often leave the other behind to care for chicks while it searches for a new mate. KenCanning / Getty Images

Plovers are a family of shorebirds known for their long legs, straight bills, and charismatic personalities. They also have an interesting relationship quirk. While other birds are more likely to break up if they have an unsuccessful breeding attempt, plovers are more likely to divorce after successful mating.

The behavior seems counterintuitive. Usually, evolution predicts that if mating is successful, then a pair will stay together for another attempt. But researchers found that isn't the case with these birds.

Two dozen scientists from 13 countries analyzed the mating behavior of eight different plover species in 14 populations around the world. 

Typically, the birds lay two to four eggs and can breed as many as four times each season. Plover chicks mature quickly and become independent just a month after hatching.

In some plover species, either parent can leave the nest to breed with a new mate. Researchers were surprised to find that pairs that had successfully mated and raised chicks were more likely to “divorce,” while pairs that did not have chicks were more likely to stay together and try to breed again.

“In contrast to many other bird species which tend to split up after nest failure, plovers gain reproductive benefits by divorcing after a successful breeding, and quickly initiate another breeding with a new mate, so as to improve the number of the offspring,” study first author Naerhulan Halimubieke, a PhD student at the Milner Centre for Evolution at the University of Bath in the U.K., tells Treehugger.

Females were more likely to leave the nest than males. Those that left were more likely to have more offspring during a mating season than those that stuck with a single mate. 

Plovers that divorce their mates also tend to travel farther distances when looking for new partners.

Helping the Species

The findings, published in the journal Scientific Reports, also suggest several other factors that could influence this mating behavior.  

Ambient temperature can have an impact. Breeding season is longer in warmer environments like the tropics than cold environments like the arctic, Halimubieke points out. So birds from warmer habitats don’t feel the pressure of time constraints as birds in colder climates.

Plover chicks are precocial, meaning they are relatively independent from the time they are born, so they don't need as much immediate care from both parents. “Thus one parent can be freed from parenting and searching for new mates,” Halimubieke says. 

Because there are more unmated male plovers than females, it’s often the females that leave the nest to go on breeding with unattached males, he says. 

Improving the understanding of the plovers’ breeding behavior can help preserve the species' diversity, the researchers say.

“Shorebirds are extraordinary and beautiful birds, but they have a problem. Many populations are in decline and such crisis is neglected by the public,” Halimubieke adds.

“Given that breeding behavior is one important aspect that affects population productivity, this work thus has great implications for preserving the diversity of this group of species.”