Northern Prairie Wildlife Research Center
Description: The osprey is a large raptor, measuring 22-25 inches (56-63.5 cm) in length, and having a wingspan of 4.5-6 feet ( 1.4-1 .8 m). It has brown upperparts, white underparts, a white head with a small dark patch in the crown and a dark eyestripe. In flight, a sharp bend or crook with a black patch at the "wrist" is visible in its long, narrow wing.
Habitat and Habits: Osprey habitat includes lakes, large rivers and coastal bays. It is adapted to its fish-eating diet with a reversible front toe and spiny nodules under its toes (spicules) to aid in grasping fish captured by plunge-diving feet first. Ospreys nest at the tops of large living or dead trees, on cliffs, on utility poles or on other tall manmade structures. Clutch size ranges from two to four eggs with hatching in about 30 days. Young fly at 44-59 days and are dependent on parents for 6-12 weeks.
Distribution: This species has a worldwide distribution. In North America, the osprey breeds from northern Saskatchewan, Labrador and Newfoundland in Canada, to the Great Lakes states and along the Pacific and Atlantic coasts. In South Dakota, it is a historical nester in the southeastern part of the state and an uncommon migrant. Many summer observations and the first modern (1991 ) successful osprey nest in the state raise hopes for the future of this species in South Dakota.
Conservation Measures: The osprey was drastically reduced in number as a result of DDT accumulation in fish, the exclusive prey of this bird. In areas where ospreys nest, construction of nesting platforms, creation of osprey management areas, reintroduction by hacking and protection of nesting sites will help to build and maintain a stable population.