Parasites benefit by sharing

Although half the known brood parasites—birds that lay their eggs in other bird's nests—set about murdering their nest mates just after hatching, some parasitic species, such as Clamator cuckoos, Vidua finches, and Molothrus cowbirds, seem to tolerate the presence of other nestlings. And new findings published this week in Science show that brown-headed cowbird chicks actually grow fastest when they share the nest.

"Our results contribute to a growing literature which suggests that individuals can enjoy personal benefits from living in groups, even if they are unrelated to the other group members," lead author Rebecca Kilner, at the University of Cambridge, UK, told The Scientist.

Kilner, together with colleagues at the University of Auckland and the University of California, Berkeley, first looked at the results of previous research from a new angle, by asking how cowbird chicks fared in relation to the number of host chicks present in the nest. ...