Shortly after WWII DDT became a widely used pesticide in the U.S.
Eagle ingested the DDT by eating contaminated fish, causing their egg shells to thin and be crushed by the mom eagle during incubation.
By the 1960s there were fewer than 500 nesting pairs of Eagles in the lower 48 states and was listed as an endangered species in 1967.
So in 1972 the Environmental Protection Agency banned the pesticide DDT, which was the first step in reviving the Eagle population.
Now there are more than 7,000 nesting pairs of eagles in the lower 48 states.
A lot of those eagles have returned to the Mid-west because it is home to the largest Wildlife Refuge in the lower 48 states.
Wabasha, Minnesota is the start of the refuge where the National Eagle Center is located.
The center invites visitors to come and see the eagles up close and watch them in the wild.
Officials at the center say they it's important to keep up the awareness as new threats like West Nile virus impose on eagles everyday, but remains optimistic that the future looks good for eagles.