Ospreys, also known as “fish hawks,” are a widely distributed raptor species found on every continent except Antarctica. These birds are recognized for their distinctive appearance and their diet, which consists almost exclusively of fish. Ospreys are unique among raptors for their specialized physical characteristics, such as oily, water-repellent feathers, and feet with barbed pads and reversible outer toes, which aid in grasping slippery prey. Many osprey populations undertake remarkable long-distance migrations annually, traveling thousands of miles between their breeding and non-breeding grounds.
The Driving Forces Behind Osprey Migration
Ospreys migrate primarily due to the seasonal availability of their main food source: fish. As colder temperatures arrive in northern latitudes, water bodies can freeze over, making fish inaccessible. Even if waters do not completely freeze, fish tend to move to deeper, warmer areas, making them harder to catch. This food scarcity drives their southward movement to warmer regions.
In addition to food availability, the need for suitable breeding conditions drives their spring migration back north. Northern breeding grounds offer longer daylight hours during the summer, providing more time for adult ospreys to hunt and feed their young. These areas also typically have fewer predators for eggs and chicks and an abundance of fish during the warmer months, creating ideal conditions for successful reproduction.
North American Osprey Wintering Grounds
Most North American ospreys migrate to Central and South America for the winter. Their specific destinations vary depending on their breeding origin within North America.
Ospreys from the eastern United States primarily migrate to South America, with a smaller proportion wintering in the Caribbean Basin. These birds often follow the Atlantic Coast southward, funneling through Florida, then crossing the Caribbean Sea via Cuba and Hispaniola (Haiti and the Dominican Republic) to reach the South American mainland. They scatter across various South American countries, including Venezuela, Colombia, Brazil, Paraguay, and even Argentina. Some individuals from the eastern U.S. may travel up to 7,000 miles from their nesting sites to southern South America.
Ospreys breeding in the midwestern United States predominantly winter in Mexico, with some also reaching the Caribbean Basin and South America. These birds might travel south through Texas and Mexico, or cross the Gulf of Mexico to the Yucatan Peninsula before continuing through Central America. Ospreys from western North America typically migrate directly south to Mexico and Central America, generally not extending their journey as far as South America or the Caribbean Basin. Regardless of their specific routes, adult ospreys exhibit strong fidelity, returning to the same wintering sites year after year.
European and Asian Osprey Wintering Grounds
Most European ospreys travel south to Africa for the winter. British ospreys, for instance, commonly overwinter in West African countries such as Senegal and The Gambia, making journeys of over 4,500 kilometers.
Ospreys from Scandinavia and Eastern Europe tend to migrate to East and South Africa. Birds breeding further east in Russia typically move south to coastal Arabia, the Indian subcontinent, and Southeast Asia. For example, a tagged osprey from Norway was tracked wintering in western India. While most populations are migratory, some osprey populations in warmer regions, such as parts of Florida, Mexico, the Caribbean, and the Mediterranean, are sedentary and do not migrate. Australasian ospreys also tend to be non-migratory.