Osprey (Pandion haliaetus) is a large and powerful raptor (bird of prey).
Osprey is one of the most widespread birds in the world. In fact, apart from the polar and subpolar regions, whose bodies of water remain for too long covered with ice, and some isolated oceanic islands situated at low latitudes, it is found on almost all the coasts as well as at the edges of great lakes, rivers and rivers of all continents.
Description
it is the most specialized fisherman among birds of prey and an excellent example of adapting structures to a specific activity.
Its most noticeable singularities are noticeable in its hind limbs: strong and very clear legs with short and tight plumage, without the "floating" breeches of other raptors, its bare tarsi and its fingers are rather short but powerful, the plant of these is covered with hard scales with pointed projections that give them a rasp roughness.
As is the case for most raptors, the female is larger than the male. On average, it weighs 1.6 kg compared to 1.4 kg for the male, and has an average wingspan of 163 cm against 159 cm for the male. The adult Osprey is 53 to 65 cm in length.
His anatomy is reminiscent of eagles. However, its narrow wings are sharply cranked as they unfurl, and the structure of its paws and talons is so particular that the Osprey has been placed in a separate subfamily of which it is the sole representative. , the pandionines.
Unlike other raptors, the Osprey has four equal fingers. The external finger is reversible, which allows him to grab his prey with two fingers directed forward and two back. Each finger ends with a long, sharp, curved fingernail, and the plantar sole of the legs is covered with short rigid spicules, which gives it a good grip on slippery prey. His prey are almost always fish he captures alive, hence his nickname "Eagle-fisherman."
Unique characteristics
When sighting a fish, Ospreys fly at a height of 10 to 30 m until the fish is well placed. The spectacle it offers then is simply grandiose when, huge and yet so light, it dives from the air, wings half closed and greenhouses well forward, to disappear almost completely under the surface of the wave in a big shower of water. It reappears most often a few seconds later with a fish well clasped, head forward, between the greenhouses. Fortunately, his plumage is fine and tight, especially on the legs, which prevents him from getting too wet. The Osprey carries the captured fish by placing the head of the fish in the direction of flight. He sometimes uses a single leg to hold a small fish, but normally he uses both.
Osprey Food
The Osprey is particularly interested in slow-swimming fish that stand near the surface of the water. In Canada, its preferred prey is freshwater suckers, pike and walleye of medium size. Occasionally, it feeds on fish weighing up to 2 kg in breeding ponds, to the dismay of fish farmers and sometimes even at the risk of his life. In a salty environment, it feeds mainly on plaice and tomcorn, but also on pollock, shad and smelt.
Usually, the Osprey will perch nearby to eat prey, except during the nesting season; he then brings it to the nest or to a perch near the nest. He holds the fish with a paw and tears it in pieces with its beak, devouring the head first.
Osprey is best established near transparent water surfaces, calm and inhabited by large fish.
The average of its catch is 200 to 300 grs and can go up to 500 grs - bream, pike, roach or perch.A couple and their three young people would need, from March to September,about three hundred kilograms of fish, which represents a fraction very small fish stocks in its territory.
shouting and singing "Osprey"
The Osprey is usually silent, but uses vocalizations to ask for food, when threatened, and during courtship and defense displays.
The alarm call is a series of hoarse and descending whistles "piu-piu-piu-piu". During the nuptial flights, the male emits a series of melancholy whistles "yeelp-yeelp-yeelp". We can also hear series of "kyews" sound.
Survival and mortality
The annual survival of adult Osprey (over 2 years) is quite high (maximum longevity: 24-25 years in the wild).
The survival of young and sub-adults is more difficult to assess. They are not territorial in the first year, so the chances of controlling them are lower. 43 to 60% of fledglings would still be alive after one year. Overall, out of 100 young Ospreys surviving until fledging, 37 will still be alive four years later, and will have the opportunity to breed. Eight years later, 17 of them will still be alive. Only 6 to 8 will reach the age of 12.
There are breeders over 20 years old. We quote a banded bird who lived 27 years,Osprey does not support captivity and dies there on average after two years.
source:http://www.conservewildlifenj.org/species/fieldguide/view/Pandion%20haliaetus/