Judy Diamond first became interested in the animal after a visit to New Zealand. "[New Zealanders] had the wildest stories they were telling me about it," she said.

To hear tales of the kea, visitors to New Zealand's South Island might expect to find a monkey attacking their belongings. Few would expect the 20-inch (50-centimeter) brown-green parrot to be the comical-but-destructive animal that local wildlife officials call "the clown of New Zealand's Southern Alps."

The keas' behavior may amuse visitors, but to New Zealand settlers, the charm of the birds quickly wore off. In addition to destroying property, as farmers encroached on the bird's territory in the mid-1800s, the keas developed a taste for sheep.

A war against the kea ensued, and at least 150,000 keas were killed by bounty hunters before the bird gained full protection in 1986. Only about 3,000 remain.

Evolution of a Pesky Parrot

Diamond and her husband, Alan Bond, have studied the odd behavior of the kea for almost 15 years.

"Very little was known about keas in the wild," said Diamond, until the pair began studying the bird with the help of several grants from the National Geographic Society's Committee for Research and Exploration.

Diamond and Bond first documented the parrot's social behavior, investigating how keas learn their playful and investigative habits. The team is now using field studies to compare the kea to its less-destructive relative, the kaka, hoping to find the evolutionary roots of this behavior.

Their hypothesis: that the two emerged from a single species that became separated by geography. The parrot that evolved in the northern lowlands of New Zealand became the kaka, which specialized in exploiting the area's predictable food resources.

The kea, meanwhile, evolved in the colder, less-predictable south, where they were forced to scrounge for food in an alpine environment.

"They seem to have evolved a very human-like flexibility and intelligence" due to these adverse conditions, Diamond said.

The kea, said Bond, is one of very few animal species that continue to investigate new food possibilities (including cars and bicycles) into adulthood. This flexibility allowed the kea to survive in the inhospitable mountain climate it inhabits.

Kea Population Small But Stable

Although wildlife officials have waged an aggressive education campaign about the importance of the kea in the New Zealand ecosystem, many highland residents remain hostile toward the destructive bird, Diamond said.

Because the bird is sighted regularly, many New Zealanders often remain unaware of how few keas remain in the wild, said Diamond.

"They assumed there were larger populations away from people," she explained, "[but] our data suggests that in the backcountry there aren't very many keas."

To the dismay of many farmers, motorists, and campers, the kea isn't getting any less visible. One of Diamond and Bond's most recent discoveries: Once relegated to alpine regions, the kea has begun to nest in areas that were once kaka territory.

Although the kaka once held the "competitive advantage" of the two birds, according to Bond, it is now considered an endangered species. Less adaptive than its relative, the kaka is facing a severe decline due in part to human-introduced mammals.

With a broader range of territory, will the kea's mischief subside? Not likely, said Bond.

"Reliance on learning, exploring, and highly destructive behavior is hardwired [into the kea]," he said.