The only North American hawk that eats live fish almost exclusively, the osprey is a common sight along lakes, rivers, marshes and seacoasts. Not able to dive more than 3 or 4 feet in the water, ospreys rely on shallow fishing areas, though they do feed in deeper waters when fish are close to the surface. Osprey will travel up to 12 miles from its nest to find food.
While 99 percent of its diet is comprised of fish, it will occasionally eat reptiles, small mammals, crustaceans and birds.
With a wingspan up to 63 inches and a body nearly 2 feet in length, ospreys are among North America’s largest and most distinctive raptors. Brown above and white below, these fish hawks have a white head with a dark stripe extending to its eye. The wing has a distinctive bend at the wrist.
Another distinguishable feature of the osprey is its reversible outer toe, which allows it to grasp its prey, typically fish, with 2 toes in front and 2 toes behind. When flying with its catch, it lines it up head first for less wind resistance.
Range and Migration
Ospreys can be found on every continent with the exception of Antarctica. North America populations breed from Alaska to Newfoundland, south along the Atlantic Coast to the Gulf of Mexico. While most populations are found along the Atlantic and Gulf coasts, other can be spotted in the Great Lakes, Rocky Mountains and on the West Coast from Washington to northern California.
In 2008, scientists tracked a 3-month-old female osprey which flew 2,700 miles from Martha’s Vineyard, Massachusetts, to French Guiana in 13 days, stopping along the way in coastal Maryland and North Carolina, the Bahamas, the Dominican Republic and a small island off the coast of Venezuela.
Osprey pairs at least 3 years old typically mate for life and return year after year to the same nest. They lay a clutch of 2-4 eggs each spring. After a nearly 5-week incubation period, the young emerge within about 5 days of each other. In times of food scarcity, the chick to hatch first will typically out compete its younger siblings. And in another 8 weeks, the young will become skilled flyers.
Their nests, made mostly of sticks, grasses and vines, can be seen in open areas atop trees, on cliffs, or man-made platforms like channel markers, utility poles, bridges or man-made nesting platforms. The nests start out relatively small, but after generations of use and additions, it can grow to 6 feet in diameter and 13 feet deep.
- In the 1950s to 1970s, osprey numbers declined when birds were poisoned from pesticides. Following the 1972 ban on the pesticide DDT, the osprey has rebounded, but they still remain listed as endangered or threatened in some states.
- Coastal development and tree removal have limited natural nesting sites in many areas, making man-made nesting structures vital to the osprey’s survival.
- Reliant on live fish as its primary food source, ospreys depend on healthy coastal and estuarine habitat, which in turn support healthy fisheries. Decades of degradation in the Gulf, compounded by the impacts of the oil spill, have presented scientists with an array of problems to solve, including coastal erosion and declining fisheries.