Osprey migration

1 WHERE ARE BRITAIN’S OSPREYS NOW?

Most ospreys that breed in the northern hemisphere migrate south for winter, because when lakes freeze they can’t fish. British birds head to West Africa, mainly Senegal and Gambia, though a few now winter in Portugal and Spain. They have exceptionally long wings and can make longer sea crossings than other birds of prey, which manage only a few hours over water.

One tagged osprey flew an amazing 350km across the Bay of Biscay.

2 WHAT DO THEY DO IN WINTER?

Tagging studies show that ospreys winter along coasts and estuaries, switching their diet to salt-water fish. They have no trouble fishing in the sea. Food can be so plentiful that they spend over threequarters of the day perched in trees by the shore, sometimes in groups of several dozen. If holidaymakers on Gambian beaches look up, they may be treated to the magnificent sight of ospreys that hatched in Britain flying overhead to fish just offshore.

3 WHEN WILL THEY SET OFF HOME?

Adult ospreys begin their return journey of over 4,500km in late February or March. Not only do they return to the same nest, they use the same familiar roosting trees at stop-overs during their migration. Juveniles linger in West Africa for at least two years before making the maiden trip north to find a nesting area of their own. The Mediterranean has a few nonmigratory osprey populations, including on Menorca and Corsica, where birds survive on sea fish year-round.