Northern Prairie Wildlife Research Center
STATUS: Locally common to uncommon; population declining due to destruction of habitat, pesticides, human disturbance, and reduction of food resources.
HABITAT: Nearly cosmopolitan distribution, occurring on every continent except Antarctica. Occupies a wide range of habitats in association with water, primarily near lakes, rivers, and along coastal waters with adequate supplies of fish.
SPECIAL HABITAT REQUIREMENTS: Elevated nest sites near water with rich fish resources.
NEST: Nests in loose colonies or singly, and uses a wide variety of structures to support large stick nests, which may be 60 feet or more above ground. Prefers a snag in or near water, with a broken top or side limbs able to support the nest. Prefers tall snags that provide good visibility and security. Also nests on pilings, utility poles, duck blinds, buildings, steel towers for transmission lines, windmills, channel markers, fences, a wide variety of living, partially dead, or dead trees, wooden platforms in marshes, on cliffs, and sometimes on the ground. Nest site may be used by the same pair year after year.
FOOD: Feeds almost exclusively on fish; flies 50 to 100 feet above (preferably shallow) water, then hovers and plunges into the water to catch fish. Also eats frogs, snakes, ducks, crows, night-herons, and small mammals.
REFERENCES: DeGraff et al. 1980, Heintzelman 1979, Sprunt 1955, Zarn 1974a.