Like many people, birds sing to show off. Singing demands neurological sophistication and physical stamina and is thus a good signal of what fine mates (and bad opponents) they would make.rnA recent paper in Behavioral Ecology, though, goes one step further. It suggests that singing not only demonstrates how healthy a bird is, but how healthy it was. In avians, as in humans, the effects of childhood ailments can linger into adult life. And that shows up in their song.rnThe paper's authors, Linda Bischoff of the University of Bern in Switzerland and her colleagues, looked at great tits nesting in boxes in a Swiss forest. As the birds' eggs started to hatch, they removed both the nestlings and the nests from the boxes. They microwaved the nests to kill any parasites and then returned both nests and nestlings. Then they infested half the nests with 60 hen fleas each.
展开▼
