A Beaky Kiss to Calm You Down

Scientists have always had the tendency to associate complex behavior to a complex brain neocortex.

But birds tend to contradict this principle, with their intelligence located in another brain zone, still unknown.

Recently, researchers noticed in rooks a kind of behavior that was found before only in apes. Rooks nest in huge colonies, named rookeries, usually crowded in some tall trees. In such a place, every now and then, there's bound to be a fight. But after a vivid quarrel, rooks were seen making peace with ... a kiss. "Bill-twining, which looks remarkably like kissing, is rooks' chosen way to ease their tempers," said experimental psychologist Amanda Seed from the University of Cambridge, United Kingdom.

This is the first time such behavior has been documented on birds.

In many mammals, especially primates, a fight is often followed by a comfort mutual grooming with an animal not involved in the fight, a behavior suspected to decrease stress.

In chimps and bonobos, this behavior advances more: the object of their grooming is their opponent, a sign of making peace.

Rooks mate for life and use the same nest each year, having a strong social bound with the group. Group life presents advantages in defending the nest colony and foraging. But it also creates competition for nests and food items. "It's like walking a tightrope, trying to find a balance between those group benefits and your own," says Seed, "and of course that leads to arguments."

A captive group of 10 rooks, including four monogamous pairs, was observed. The paired rooks did not fight between them, but instead they often quarreled with neighbors for food or nesting material. "After such fights, the antagonists flew to their mates. The pairs preened, shared bits of food, and twined their bills," Seed reports.

This behavior was not displayed with their opponents. The kiss-and-calm-down behavior of the rooks has "remarkable similarities to behaviors among the great apes," says animal behaviorist Filippo Aureli at Liverpool John Moores University, U.K.

Biologist Frans de Waal from Emory University (who first observed in chimps the reconciliation and consolation behavior) thinks the birds may not actually display a consolation behavior, because the mate should initiate the calming kisses. Even so, this is clearly a complex behavior of stress release.

Photo credit: Chris Bird