Divorce Comes With Warning Signs—Even in Songbirds

Great tit songbirds usually breed with the same partner each season, but they don't necessarily mate for life. In a new study showing "the extent to which social behavior influences animals' lives," researchers describe the "divorce" of certain great tit couples after the job of raising their nestlings is done. And there are early warning signs, says Oxford University PhD student Adelaide Abraham, lead author of the study published Wednesday in Proceedings of the Royal Society B, who fitted the black and yellow birds found throughout Europe and Asia with radio tags that would ping at various feeders. After baby birds left their nests and summer turned to fall, researchers noticed several "faithful" mating pairs visiting feeders together, per NPR.

But the "divorcing" pairs didn't associate as much, and "that only increases as the winter goes on," Abraham tells NPR. Humans who've gone through divorce might understand the urge. But Abraham says it was surprising to see these behaviors among songbirds. It appears some opt to move on quickly after nesting, allowing them to develop new relationships over the winter months, before the spring nesting season arrives again. "This suggests that winter socializing during the non-breeding season is indicative of what will be seen in the following mating period," per a release. As Abraham sums it up, per NPR, "There is actually a lot more going on in those flocks of birds out your window than you think there is."