Birds infer their partner's desires during bonding ritual

Ars Technica » Scientific Method 2013-02-05

The corvids, a group of birds that includes crows and jays, display some of the most complex behaviors seen in any birds: tool use, an ability to associate faces with behaviors, and the recognition of when one of their peers has died. In a number of cases, these birds have been seen exhibiting behaviors that, until recently, were thought to be limited to primates. Now, researchers suggest there's another complex behavior we can add to their impressive list: the ability to infer the desires of others.

This behavior was observed in Eurasian jays, a species ranging from Western Europe to India. Pairs of jays engage in courtship behavior that includes the sharing of food, which helps in the formation and maintenance of pair-bonds. Researchers at Cambridge decided to test whether the males could successfully figure out what sort of food their partners might want.

You might think that, to a bird, one meal is as good as any other. But at least for jays, you'd be wrong. The birds actually aim for variety when they make caches of food to eat later, trying to ensure they'll have a mixture of food to enjoy the next day. The researchers confirmed that Eurasian jays have a similar desire for variety. If researchers pre-fed the jays a meal of wax moth larvae (mmm!) and then offered them a mix of that and mealworm larvae (double mmm!), the birds preferentially ate the mealworms. If the researchers did that after a meal of bird food, the birds chose the wax moths at a greater frequency.

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