Pandion haliaetus
They are bright white underneath, with dark brown patches at the carpal joints and a mottled dark brown necklace. Other identifying markings include a dark stripe through each eye, and a dark brown back. The feet of this species are pale blue-gray, and the beak is black. Juvenile ospreys resemble adults, but have a somewhat speckled appearance due to buff-colored tips on their dark brown upper-wing and back coverts and a less well-defined necklace. Juveniles also have an orange-red iris, rather than the yellow iris that is typical of adults. Juvenile plumage is replaced by adult plumage by 18 months of age. On average, while not necessarily longer, female ospreys are 20% heavier than males and have a wingspan that is 5 to 10% greater.
Not Threatened.
They are bright white underneath, with dark brown patches at the carpal joints and a mottled dark brown necklace. Other identifying markings include a dark stripe through each eye, and a dark brown back. The feet of this species are pale blue-gray, and the beak is black. Juvenile ospreys resemble adults, but have a somewhat speckled appearance due to buff-colored tips on their dark brown upper-wing and back coverts and a less well-defined necklace. Juveniles also have an orange-red iris, rather than the yellow iris that is typical of adults. Juvenile plumage is replaced by adult plumage by 18 months of age. On average, while not necessarily longer, female ospreys are 20% heavier than males and have a wingspan that is 5 to 10% greater.
Ospreys are large birds of prey (55 to 58 cm long), with a wingspan ranging from 145 to 170 cm. Their long wings have a characteristic bend at the carpal ("wrist") joints.
Taxonomy:
- Falco Haliaetus Linnaeus, 1758, Europe = Sweden. Sometimes included within family Accipitridae, but usually in its own subfamily, Pandioninae. Race melvillensis often applied to birds from Indonesia to N Australia, but probably not valid; similar to cristatus. Four subspecies currently recognized. (source: Handbook of the Birds of World)
Subspecies and Distribution:
- * haliaetus (Linnaeus, 1758) - Scandinavia E to Japan and S to Mediterranean, Red Sea and Cape Verde Is; winters S to S Africa, India, W Indonesia and Philippines. * carolinensis (Gmelin, 1788) - Labrador W to Alaska and S to Florida and Arizona; winters S to Peru and S Brazil. * ridgwayi Maynard, 1887 - Caribbean, including Bahamas, Cuba and Belize. * cristatus (Vieillot, 1816) - Australia E to New Caledonia, and N through New Guinea to Java and Sulawesi.
Ospreys have a wide distribution because they are able to live almost anywhere where there are safe nest sites and shallow water with abundant fish. Nests are generally found within 3 to 5 km of a water body such as a salt marsh, mangrove (Rhizophora) swamp, cypress (Taxodium) swamp, lake, bog, reservoir or river. The frequency with which each of these habitat types is used varies by geographic region. Ospreys choose structures that can support a bulky nest, and that are safe from ground-based predators. Nest sites can be safe from predators either by being difficult for a predator to climb (e.g. on a cliff) or by being over water or on a small island. Over-water nest sites that are often used by ospreys include buoys and channel markers, dead trees and artificial nest platforms. Ospreys have also been known to nest on various man-made structures, such as power poles, duck blinds, communication towers, buildings and even billboards.
Ospreys are unusual among raptors for being piscivores. Their diet consists almost exclusively of fish (≥99% of prey items). They are generally opportunistic, and will eat whatever fish species are accessible to them – either in shallow waters, or near the surface of deeper waters. Studies in North America have documented more than 80 different prey species of ospreys. However, 2 or 3 common species may dominate the diet of local ospreys in a given area.
The breeding season of ospreys differs between populations. Non-migratory populations breed in the winter and spring, laying eggs between December and March. The breeding season of migratory populations occurs in the spring and summer, with egg laying in April and May. Two to four eggs are laid over a period of several days, each 1 to 2 days apart. Both the male and female incubate the eggs, which hatch after approximately 40 days. Because incubation starts when the first egg is laid, the eggs hatch asynchronously in the order in which they were laid. Chicks that hatch first are larger and have a competitive advantage over those that are hatch later. If food becomes scarce, the smaller chicks are less successful in competing for food, and often die.