Long incubation times may defend birds against parasites
(PHYSorg.com Biology)

Some tropical birds have longer egg incubation times than their temperate cousins, even though their habitat is teeming with egg-eating predators. The reason why has long been a mystery, but a new study from The Auk: Ornithological Advances applies new methods to confirm the evidence for an old hypothesis-that a longer development period leads to a stronger, more efficient immune system.