It's October in the Upper Mississippi Valley, and the weather is mild. Plucking coots and mallards from the water, the bald eagles show off their aerial antics.

Watch a sneak peek of "American Eagle" -- Coming to NATURE Fall 2008: "American Eagle" is the first HD hour on bald eagles ever.

In 1963, there were less than 500 bald eagle breeding pairs in the lower 48 states. Click around these interactive maps to find out how many pairs there were from 1990 to 2000.

In 1963, there were less than 500 bald eagle breeding pairs in the lower 48 states. Click around these interactive maps to find out how many pairs there were from 1990 to 2000.

In 1963, there were less than 500 bald eagle breeding pairs in the lower 48 states. Click around these interactive maps to find out how many pairs there were from 1990 to 2000.

In 1963, there were less than 500 bald eagle breeding pairs in the lower 48 states. Click around these interactive maps to find out how many pairs there were from 1990 to 2000.

In 1963, there were less than 500 bald eagle breeding pairs in the lower 48 states. Click around these interactive maps to find out how many pairs there were from 1990 to 2000.

Of the 4,000 or so species of mammals, only a handful of animals have ever been thought to mate for life.

Biologists trying to restore eagle populations around the world face a difficult challenge. But there are success stories -- and the restoration of America's Bald Eagle is one of the most dramatic.