BIRDS in the warmer climates of the southern hemisphere tend to abandon their
young when threatened by predators. But their cousins living in the colder
regions of the north are more likely to stick around, say a pair of evolutionary
ecologists. They argue that the heartless behaviour of some birds is in the best
interests of these species.
In mild climes, birds have a long breeding life and tend to have fewer
offspring each season. But birds living in colder areas are less likely to
survive winters and migrations, so compensate by producing more chicks.
According to evolutionary theory, parents…
