Bald eagle is threatened even the situation ia a bit better but soon we are back on the endangered situation.
The Bald Eagle was endangered from the 1950's to the 1990's because of pesticides, such as DDT, that were later banned in the US. These chemicals made the eagle eggs very fragile, causing them to break when the eagles attempted to sit the nest. Some chicks survived but were unhealthy, and had problems reproducing. There were also mutations among the chicks, and many didn't survive long after hatching.
The pesticides were not only ingested directly, but the amounts were compounded through the food chain of the Bald Eagle as well. Even when the use of the chemicals was stopped, the eagles continued to be exposed through lingering contamination of their food and water.
The food source and water supply for most Bald Eagles is generally clear of most pesticides in the U.S. today, since their use has been strictly regulated. The pesticides were the major factor in the decline of this species, but human disturbances, including habitat loss, competition for food, hunting, and poisoning eagles are all factors that had an impact on the populations. The problems were so serious that protection for the species was enacted in 1940. The populations had been showing good signs of improvement with the new protection provided in 1940, until DDT and other such pesticides first came on the scene, and again caused population drops. DDT was eventually banned in 1972.