The weka: Nature's dumbest?
New Zealand
and Madagascar are similar in many respects. Both are large island nations in the southern hemisphere. Both split off from their respective mainlands tens of millions of years ago, and are populated with a fascinating variety of plants and animals found nowhere else on earth. In both places, the survival of these native plants and animals is threatened by species introduced by humans, who arrived only within the last two thousand years. And both islands are far colder during the winter months than any civilized place has a right to be. But there is an intriguing difference between New Zealand and Madagascar—in New Zealand, the birds became mammals, while in Madagascar, the mammals became birds.
In New Zealand, with the exception of two bats, there were never any land mammals. The role of grazing and ground foraging was taken over by birds. Because these birds were not troubled by predators, many became flightless and dimwitted, like the weka. In Madagascar on the other hand, though there are plenty of birds, the task of dispersing the seeds of rainforest plants has largely been taken over by lemurs! And since lemurs are far more hesitant than birds to stray far from their rainforest surroundings, this means that a patch of land in Madagascar must be very near existing rainforest to regenerate rainforest “naturally.”
