Birds Are Fooling Around and Getting Divorced

Most birds are monogamous(ish) and a few species even mate for life, but divorce is also common, and may even be on the rise. A German-Chinese research team analyzed data on 232 bird species to document the avian discontent.

It won’t surprise humans to hear that bird breakups are largely due to cheating, specifically male promiscuity. “Plovers, swallows, martins, orioles, and blackbirds had high divorce rates and high male promiscuity, whereas petrels, albatrosses, geese, and swans had low divorce rates and low male promiscuity,” the scientists write.

On the other hand, when females fool around there’s not much discord between the sexes. Oddly enough, female promiscuity may even prompt males to be better caregivers. “Each male, uncertain about his paternity, may invest more effort in caring for the offspring to ensure their survival,” says co-author Zitan Song.

The researchers identified another reason for divorce: long-distance relationships. Many birds fly thousands of miles every year to breed and follow the seasons’ food cycles. “Married” couples get separated on the commute, arrive at their destinations at different times, or even die on the way. All these factors (especially the dying) could lead to permanent separation.

The researchers’ findings are published in Proceedings of the Royal Society B.

Photo credit: Ying Qin