英语听力：猛玛象进城记—10

Where purple martins had once laid their eggs in hollow threes, in time, they came to rely almost totally on people to provide nests for them.

These artificial nests were made from dried out squashes known as gourds. The shape made them perfect nesting sites for these birds. But what triggered this special relationship in the first place? It’s possible the insect-eating martins helped to control pests living around Native American camps. Whatever the original reason, the traditional tie between people and purple martins survives to this day. But now, in keeping with the modern world, hollow gourds have often been replaced by high-rise apartment blocks.

This special relationship between purple martins and people is one of the few in North America to cross cultural boundaries between native groups and European settlers. Other animals to cross this cultural divide did so for different reasons.

More than 50 million wild turkeys were living in North America when the first Europeans arrived. They were occasionally hunted by the native people, but the European settlers had a taste for turkey and they took this to extremes. As hunting intensified, wild turkey populations plummeted.

The turkey became a central part of Thanksgiving Day celebrations and was almost hunted to extinction.