Marsh Hawk
331. Circus hudsonius. 19 inches.
The adults of this species are very light colored; bluish gray above and white beneath. Young birds of the first two years are brown, much lighter on the under parts. In both the old and young they have a large white patch at the base of the tail. Nest is made in and on swampy ground; four to seven eggs; white (1.80 × 1.40).