The western osprey, also known as the sea hawk, river hawk, and fish hawk, is a large, long-winged bird of prey with a short tail. It is the only bird of prey to feed almost exclusively on fish and its species name derives from the Greek hals meaning salt or sea and aetos meaning eagle.
Like owls, it has an opposable toe which means it can grip onto its prey in flight, and its nostrils close to keep water out when it dives. It can be found across the world except in Antarctica and has a global population of about 460,000 birds.
Breeding pairs: 200 – 250 pairs
Family: Osprey
Ospreys have dark brown upperparts and white underparts with small brown spots on the upper breast which form a necklace. The underwings are white with a dark brown patch on the carpal joint and the tail is brown with white bars.
The head is white with conspicuous dark brown stipes through the eyes that extend to the nape which is covered with longer feathers. The hooked bill is black, the eyes are yellow, and the legs and feet are pale slate grey.
Males and females are similar, but the female is slightly larger and she has darker plumage overall and darker streaks on the breast.
Juvenile ospreys have dark brown plumage with pale buff edges on the upperparts, and the breast necklace is less conspicuous. They have orange-red eyes.
Ospreys breed between April and July. They are monogamous and produce 1 brood a season. They nest in dead trees or on man-made structures such as poles, towers, and other tall buildings. Both male and female build the bulky nest from sticks which is lined with softer materials including grasses, kelp, cow dung, and seaweed, as well as rubbish such as cardboard, fishing line, and even plastic bags. Pairs use the same nest each year and add more material before a new clutch is laid.
Ospreys lay 2-4 pale pink or whiteish eggs with reddish-brown or olive markings, which are incubated by both parents for about 40 days. The male guards the nest from other males and brings food to female during this time.
Chicks are covered in white down when they hatch which turns dark brown at about 10 days. The first chick to hatch is larger than the others and the smallest often doesn’t survive particularly if food is scarce. Both parents feed the chicks with fish brought by the male to the nest. They fledge at about 50-75 days after hatching and although they can hunt the parents will feed them for a few more weeks. They reach sexual maturity at 3 years.
Fish makes up about 99% of an osprey’s diet, but it will also take birds, snakes and small rodents.
It feeds twice daily, and forages by flying over water and hovering once the prey has been spotted, before diving into the water feet- first to snatch the fish.
Ospreys are found in Scotland and north east England near large bodies of freshwater. During passage migration they can be found in southern England.
Ospreys became extinct in the UK in the early 20th century. Scandinavian ospreys then moved to Britain and started breeding in 1954.
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I think I saw one of these riding thermals above a lake in the Brecon Beacons – is that likely?
Was surprised to find one hunched over the the scattered plumage of a collared dove here in Mid Wales -Powys.
We get many different birds in the garden, but this is the first time I’ve seen an osprey here.