Description: Spectacular fish-eating birds of prey, ospreys have a wingspan of nearly five feet. Their white head and undersides, contrast with the rich brown upper parts.

History: Ospreys were probably widespread across Britain in the past, especially before the huge land-drainage schemes in the 17th century which removed much of their inland habitat. There were probably between 500 and 1,000 pairs in Britain, but shooting and egg-collecting increased during the 19th century, and the population crashed. The last English ospreys bred in Gloucestershire in 1840 and, after the final pair nested in Argyll in 1916, they were gone from Scotland too.

Ospreys were extinct as a breeding species in the UK between 1916 and 1954, when they re colonised Scotland from a nest at Loch Garten, now an RSPB reserve. Breeding success was low until 1959 when intensive wardening increased the security given to the birds.

For more information on how to see many other wild birds why not visit the RSPB's Aren't Birds Brilliant website

Lifecycle: Ospreys spend the winter in Africa. Migrant birds on their way to and from Scotland turn up at many reservoirs, lakes and estuaries around the UK in spring and autumn.

Ospreys are found on all continents, except Antarctica. Male and female ospreys look similar, but - as with most birds of prey - the female is bigger. Young birds are a little paler, and more spotted above. Ospreys don't usually return to Britain in the year after they hatch: they stay in Africa for two or three years. When they do return to Europe, they often come back to the area where they hatched, which is why they spread so slowly. The female osprey does most of the incubation with the male giving her approximately 30 minute breaks in the morning and evening.

Most Scottish ospreys nest in trees, but elsewhere in the world, they nest on pylons, on cliffs, or even on the shore where there are no predators of eggs. Artificial nests and platforms have been built to encourage ospreys into suitable areas in Scotland - about one-third of all Scottish ospreys use these.

Ospreys can catch and carry fish weighing up to one kilogram. They hold fish facing forwards to reduce air resistance as they fly. They will fly up to eight miles (13 kilometres) to feed, with birds nesting near the coast often using estuaries to find flatfish and mullet. In Autumn, ospreys leave Scotland for west Africa. The females leave first, while males stay with the young birds to show them where and how to fish. The males leave in late August, with juveniles following several weeks later. They find their way to Africa without any help from their parents.

Cumbrian Ospreys: In 2001 a pair of ospreys which nested beside Bassenthwaite Lake became the first wild osprey to breed in the Lake District for over 150 years.

The birds were encouraged to stay with the help of a purpose built nest provided by the Forestry Commission and the Lake District National Park. This was the culmination of several years of hard work, the RSPB joined the partnership to provide extra support. Ospreys have summered in the Lake District since the mid 1990's, on their return in 2001 they immediately added sticks to the nest.

Once the eggs were laid, wardens kept a round the clock watch to prevent disturbance and deter egg thieves. Ospreys usually lay three eggs, which take about six weeks to hatch. The young stay in the nest for six or seven weeks. In late summer, the adult female will migrate south, leaving the male to teach the youngsters the art of fishing.

Bassenthwaite Lake is a National Nature Reserve, owned and managed by the Lake District National Park. Most of the surrounding woodland is managed by the Forestry Commission and provides valuable habitats for wildlife.

Other English Ospreys: Leicestershire and Rutland Wildlife Trust and Anglian Water have reintroduced Ospreys to Central England at Rutland Water.

Threats: Although in the UK the osprey population has doubled during the 1990s, ospreys remain the fourth rarest bird of prey in the UK. Their eggs, are stolen by collectors and if water quality deteriorates, a reduction in fish could have a dramatic effect on the number of young birds raised. Finally as ospreys migrate, they are vulnerable to habitat changes across southern Europe and Africa, and risk being shot by hunters.