Raptors don't lie. At least, not with plastic. Black kites are a raptor variety that lives on multiple continents, and like several other varieties of bird (including the crafty bowerbirds), they're avid decorators. For whatever reason, these black kites are terribly fond of white plastic, and the birds use these bits of our refuse to decorate their nests. Scientists who studied these birds in Spain report in Science this week that there is a meaning—and a strict honesty—to the decoration scheme.
They found that, several weeks before females laid eggs, birds festooned their nests with pieces of white plastic. Fitter birds, in possession of the best territory, tended to use more plastic. Weaker birds, with less-desirable territory, used less. Elderly and very young birds used none. Territorial confrontations are common among kites, and proved closely linked to displays of plastic. Kites with much plastic in their nest were rarely challenged, ...
