Where Do Ospreys Migrate? Routes From Europe and the US

Why ospreys migrate

The osprey eats almost nothing but live fish caught near the surface. When lakes and rivers in Canada, the northern United States, Scotland or Scandinavia freeze, that food becomes impossible to reach. Northern ospreys therefore leave in late summer and fall for places where open water and fish are available all winter.

Ospreys are only partial migrants as a species. Birds in mild places with year-round fishing, such as the Caribbean, southern Florida, Baja California, parts of the Mediterranean and Australia, mostly stay where they are.

Where North American ospreys go

Ospreys from eastern North America mostly winter in South America, especially in Venezuela, Colombia and the Amazon basin of Brazil, and some reach Bolivia and northern Argentina. Many follow the Atlantic coast south to Florida, then island-hop across Cuba and Hispaniola and cross the Caribbean Sea to the northern coast of South America.

Satellite tracking has shown that some birds take bolder routes and fly long distances over open ocean. Others cross the Gulf of Mexico or travel through Central America.

Ospreys from western North America tend to winter closer to home, in Mexico and Central America, with fewer going on to South America. Some birds from Florida and California do not migrate at all.

Where European ospreys go

Ospreys from Scotland, England, Wales, Scandinavia and Germany mostly winter in West Africa. Common wintering areas include the coasts and rivers of Senegal, the Gambia, Guinea-Bissau, Mauritania, Guinea and Sierra Leone, along with lakes and rivers farther inland. A smaller number winter in Spain or Portugal instead.

The typical route from Britain runs south through France and Spain, across the Strait of Gibraltar or the western Mediterranean and over the Sahara. Ospreys from farther east in Europe and Russia tend to winter farther east and south in Africa, and some Asian ospreys winter in India and Southeast Asia.

How far and how fast?

Migration distances depend on where a bird breeds and winters.

Swedish ospreys fitted with satellite tags averaged about 260–280 km (160–175 mi) a day, with a maximum of about 430 km (270 mi). Many birds complete their journey in two to six weeks, including stopovers where they rest and fish for a few days. Fall migration is usually slower than spring migration, with more and longer stopovers, because adults are in a hurry to reclaim their nests in spring.

Ospreys mostly fly by day, using rising warm air and steady flapping. Unlike many broad-winged raptors, they will cross large stretches of water and sometimes keep flying at night over the sea or desert.

What tracking revealed

Since the 1990s, ringing and satellite tags have changed what we know about osprey migration. Some of the main findings:

• Partners travel separately. Mated pairs leave and winter apart and reunite at the nest in spring.
• Females leave first. In Sweden, females tended to set off earlier than males in fall, and young birds left last.
• Young birds travel alone. Juveniles migrate without their parents, so their route is instinctive rather than learned on the first trip.
• Faithful to winter sites. Adults often return to the same stretch of river or coast in Africa or South America every winter.
• Migration is dangerous. In the Swedish study more than half of yearly deaths happened during migration, many during the Sahara crossing in spring.

Young ospreys stay south

One of the most striking facts about osprey migration is what young birds do after their first trip. Instead of returning north the next spring, most young ospreys stay on their wintering grounds for roughly 18 months. They come back north for the first time at about two years old and usually start breeding at three to five.

During that time they practice fishing, grow their adult feathers and avoid the risks of a second long migration. Many still die in their first year, mostly from starvation, collisions or storms.

Return in spring

Adults head north in late winter and early spring. In Britain, the first ospreys usually arrive in late March, and the return of famous birds to webcam nests such as those in Scotland and at Rutland Water is eagerly watched. In the northeastern United States many ospreys are back in early April. Each pair then reclaims its old nest; learn more in where do ospreys nest?, or see how they feed on arrival in how do ospreys catch fish?