Kea, Bird of Paradox: The Evolution and Behavior of a New Zealand Parrot

New Zealand, noted life scientist Jared Diamond has remarked, offers science an approximation of studying life on other planets, because the islands of New Zealand lie so distant from other landmasses that their flora and fauna are markedly unlike those of other places. Of particular interest to biologists is the kea, Nestor notabilis, a small parrot found only in the alpine beech forests of South Island, and one that has evolved in curious ways. A survivor of the great wave of extinctions that occurred when humans arrived in New Zealand a thousand years ago, the kea has long been hunted, especially by European ranchers who found it a danger to their livestock--for, as Judy Diamond and Alan Bond write, while the kea once preferred to feed on insect larvae, it shifted its dietary habits with the arrival of new food sources. This transformation, the authors suggest, speaks to the bird's adaptability and intelligence. With the change to carrion eating, the kea's population grew, although it is now again in decline. And with that change, the authors write, new characteristics emerged, so that kea groups are now male-dominated, aggressive, and hierarchically organized, unusually so for an avian species. Diamond and Bond have conducted long-scale fieldwork among keas in their native habitat, and their well-written study speaks beyond the description of one species to the benefits--and limitations--of evolutionary flexibility in general. --Gregory McNamee