Osprey

Ospreys eat almost only fish.

They fly over the water and look down. When they see a fish, they dive in feet first and grab it with their claws!

Almost everything an osprey eats is live fish. It flies or hovers over the water, spots a fish near the surface, then dives feet first to grab it in its talons. Fish it catches are usually about 15 to 33 centimeters long.

Ospreys are excellent at fishing. Studies found they catch a fish on at least 1 in every 4 dives, and sometimes on 7 dives out of 10. On average they hunt for only about 12 minutes before making a catch.

The IUCN describes a diet almost entirely of live fish; Cornell reports that in North America more than 80 fish species, fresh and saltwater, make up 99 percent of the diet, usually 6 to 13 inches long and one-third to two-thirds of a pound, with a record catch of about 2.5 pounds. Birds, snakes, voles and other prey are taken only very rarely.

Ospreys search on steady wingbeats or by circling, often hover briefly, then plunge feet first; the RSPB notes they also snatch fish near the surface in low flight. Across several studies, at least one dive in four succeeded and sometimes 70 percent, after an average of about 12 minutes' hunting. They probably get most of their water from their prey.

In spring, a male osprey does a sky dance over the nest.

He flies up and down with a fish in his feet, calling loudly. Many ospreys fly very far every year.

Ospreys mostly live alone outside the breeding season, and they usually migrate alone. At the nest, a pair guards only the area right around it.

In spring, the male performs a sky dance: carrying a fish or a stick, he hovers and swoops high above the nest, calling loudly, for ten minutes or more. Many ospreys travel very far. One tracked osprey flew about 4,350 kilometers in 13 days, from Massachusetts to French Guiana.

Ospreys are entirely diurnal and generally solitary, roosting alone or in small winter flocks and usually migrating alone, though they may gather at roosts or rich food sources (IUCN, Cornell). They migrate on broad fronts, crossing open water with flapping flight. Nesting birds defend only the nest's immediate surroundings.

In the breeding season, males perform an aerial sky-dance or fish-flight: legs dangling, often carrying a fish or nest material, they alternate hovering and shallow swoops up to 600 feet (about 180 meters) above the nest for ten minutes or more, calling repeatedly. Cornell estimates an osprey may fly more than 160,000 migration miles in its lifetime; one satellite-tracked bird flew 2,700 miles in 13 days in 2008.

Long ago, a farm chemical made many ospreys disappear.

People stopped using it, and ospreys came back. Now there are many ospreys again.

From the 1950s to the 1970s, a pesticide called DDT poisoned ospreys and made their eggshells too thin, and they disappeared from many places. After it was banned, ospreys came back. In Britain, they had died out because of hunting, but returned to nest in Scotland in 1954.

Today the IUCN lists the osprey as Least Concern, with numbers increasing. People help by putting up nest platforms. But some ospreys are still shot on migration or caught in fishing nets.

The IUCN assessed Pandion haliaetus as Least Concern in 2021, with an increasing trend and a population of 100,000 to 1,200,000 mature individuals; Partners in Flight estimates about 1.2 million. Persecution from the 18th to 20th centuries was the main historical threat, and pesticides caused steep declines in the United States from about 1950 to 1970. Cornell notes that Osprey studies supported arguments against persistent pesticides and that North American numbers grew about 1.9 percent a year from 1966 to 2019.

The RSPB reports that ospreys were extinct as UK breeders by the early 20th century until a pair nested at Loch Garten in 1954. Reintroductions in England, Spain, Italy and Portugal show signs of success. Remaining threats include shooting on migration and in wintering areas, fishing nets, wind turbines and possibly depleted fish stocks; the IUCN lists the small North African population, 130 to 146 mature individuals, as regionally Endangered.