Distant Diplomacy

Unrelated species “talk” and understand one another to avoid threats

- —Jesse Greenspan

Parasitic cuckoos are many birds' common enemy.

WHEN DANGER APPROACHES, many creatures seem to follow the ancient proverb that “the enemy of my enemy is my friend.” Researchers have recently been finding subtle ways that animals communicate with other species in this kind of cooperative defense pact.

For example, a recent study in Nature Ecology & Evolution documented more than 20 bird species on four continents that emit virtually identical “whining” calls when they spot brood parasites such as cuckoos. That call is essentially “the word for ‘cuckoo,’” says study co-lead author James Kennerley, an ornithologist at Cornell University. “And it’s recruiting individuals to come together [against] this common enemy.”