The reintroduction effort has been plagued by other problems.

This was one of the world's first successful captive breeding and reintroduction efforts for an endangered species.

The reintroduction effort off the Oregon coast was not successful.

"There are a few areas where elk are impacted," said Mr. Bangs, who has led the reintroduction effort since it began.

With the escape of captive pairs into the wild in 1982 and active reintroduction efforts, they are now making a comeback.

It is also threatening species reintroduction efforts.

It was formerly common throughout North America between the tundra and northern Mexico, where current reintroduction efforts seek to restore the population.

Until the 1950s it was found in the extreme southwestern United States, and reintroduction efforts are under way in Western and Southern Texas.

A coalition of environmental groups is attempting to have full protection restored so as not to jeopardize the success of the expanding wild population and the reintroduction efforts.

Once able captive propagation programs are necessary if extirpation should occur so that reintroduction efforts could follow.