A large form glides across the sky far over- head. It has a wingspan of just over six and a half feet, yet weighs less than ten pounds. Its body is a deep brown, while its head and tail are a bright white. It is unmistakably a bald eagle. More specifically, it is an adult bald eagle at least four or five years old due to the fully developed plumage. For a long time, this was a rare sight.
In the 19th and 20th centuries their populations declined due to hunting and egg collecting. Numbers began to increase in the mid 20th century as the government began passing laws for their protection, but this improvement was not to last. Bald eagles experienced a far worse threat when DDT was introduced in the 1940s. These ‘sea eagles’ live near rivers and lakes, and though they eat small mammals and carrion, their primary food source is fish. DDT runoff built up in fish, and found its way into eagles. It then caused bald eagles to lay eggs with very thin shells that were easily breakable. As a result, bald eagle populations plummeted. In 1972, DDT was banned in the United States, and eagle populations have been growing ever since.
In Minnesota, in acknowledgement of the dangerously low pre-1972 eagle population numbers, the bald eagle was listed as threatened on the state’s first endangered species list in 1984. Since then, many ambitious programs such as the Northern States Bald Eagle Recovery Plan have been implemented. Slowly, the bald eagle has regained its former territories in the southern half of the state and was removed from the federal endangered species list in 2007. Now, only following Alaska and Florida, Minnesota has the third largest population of breeding bald eagles in the United States. Living up to the high expectations that this establishes for eagle habitat in Minnesota, our very own Cowling Arboretum is a wonderful place to look for bald eagles. With the forest-lined Cannon River running through it, it offers prime habitat. In an article from the 1967 alumni magazine, Paul Jensen commented “the writer has seen a bald eagle over Laird,” implying an unusual event. These days, it is almost always possible to see an eagle in the Arboretum or on campus. Especially now that it is winter and eagles gather on the Cannon River, they are a common sight and one not to be missed.