题目选项分析

Zoologists warn of an imminent surge in the number of bird species that will become extinct within this century. Nevertheless, these zoologists are wrong. One need only consider the information gathered on native North American raptors, such as bald eagles and peregrine falcons. Several of these species came close to vanishing between 1900 and 1970, but since 1970, the local populations of these raptors have rebounded.

The answer to which of the following questions provides information that would be most helpful in evaluating the argument above?

【选项】To what degree have native North American raptors migrated to other parts of the world?