COVER STORY: SCIENCE
THERE can be few lazier ways of bringing up your offspring than to leave it to someone else to do it for you.
That, essentially, is what brood parasitism is. Not only is it indolent: it also underlies what humans would think of as a cruel behaviour. Parasitic birds lay their eggs in other birds’ nests, duping the brooding hen to hatch the egg as though it were her own. She then goes on to rear the hatchling. It seems to be an effective strategy, because there are approximately 300 species of birds that practise it.
