Ospreys are medium/large birds of prey. They have a length between 51 and 62 cms, a wingspan between 152 and 167 cms and they weigh between 1.5 and 2 kgs.
They are brown and white in colour, their underside and head being mostly white, and their upper side being mainly brown. They have a dark eye mask and a dark breast band, although this is more prominent in females. They have a short tail and long, narrow wings. They are also able to close their nostrils when they dive into water to catch fish.
Their feet are grey/green in colour and are specially adapted to aid them in catching fish. They have reversible outer toes and backwards facing scales on their talons to help them grip their prey.
Ospreys are found throughout the world, except in Antarctica. Their nests are usually within 3 – 5 kms of a body of water and they choose structures that are safe from predators, such as rocky outcrops, telephone poles, trees or man made platforms, on which to build their nest.
Ospreys that breed in Europe, winters in Africa and those that breed in North American and Canada winters in South America or the southern most states of the USA. Australian Ospreys do not migrate.
Ospreys mainly feed on fish. They rarely eat reptiles, rodents, salamanders and other birds. They locate their prey from the air and plunge feet first into the water to seize a fish.
Ospreys usually mate for life and breeding takes place in spring. Females will usually lay 3 – 4 eggs and they incubate them for approximately 37 days.
Osprey chicks only weigh 50 – 60 g when they hatch and they are covered in white down. At 10 days old the white down is replaced by charcoal coloured down and at 2 weeks old the down starts to be replaced by feathers. By the time the chicks reach 8 weeks old they are ready to fledge.
Ospreys become sexually mature at 3 years of age, but usually don’t breed until they are 5 years old.
Owls and Eagles will prey upon Ospreys and foxes, skunks, raccoons, snakes and other climbing animals are known to prey upon Osprey eggs and chicks.
There are four subspecies of Osprey:
Pandion haliaetus haliaetus – this subspecies breeds in Eurasia and winters in South Africa and India.
Pandion haliaetus carolinensis – this subspecies breeds in North America and the Caribbean, but winters in South America. It is generally darker in colour with a paler underside.
Pandion haliaetus ridgwayi – this subspecies is non-migratory and it inhabits the Caribbean. It has a very pale coloured head and breast and a pale eye mask.
Pandion haliaetus cristatus – this is the smallest subspecies, it is non-migratory, and it is found in Australia and Tasmania.
Ospreys are also known as: Fish Hawk, Sea Hawk or Fish Eagle.
The Osprey is the official bird of Nova Scotia in Canada and Sodermanland in Sweden.