With a record of 338 bird species encountered, Acadia National Park is considered one of the premier bird-watching areas in the country. Through the years, park staff and countless amateurs have observed the gradual extension of southern and temperate bird species to the region. Twenty-three species of warblers alone have been recorded as breeding in the park!

Acadia's offshore islands are also important nesting grounds for many birds, often marking the southern breeding limit for the species. Due to their secluded location and productive marine environment, the offshore islands administered by the park also serve as a critical nesting habitat for eiders and other sea birds, raptors, colonial birds (herons) as well as providing important wintering habitat for northern shorebirds (purple sandpipers) and harlequin ducks.

Both the swift peregrine falcon and the bald eagle actively use areas within Acadia National Park. Eagles have been studied for several years to determine their breeding activity and population changes, and their response to environmental contaminants and human-caused disturbance. Peregrine falcons have rebounded since being on the brink of extinction in the mid-1960s. The falcons were reintroduced into the park in 1984, and have been returning of their own accord to nest successfully from 1991 to the present.