Ospreys are part of the Falconiformes order which groups it with other diurnal birds of prey.  The name Pandion derives from the mythical Greek king, Pandion, who was transformed into an eagle by the gods while haliaetus is derived from the Greek “sea-eagle/osprey.”

photo M. Noonan

Ospreys are large birds, generally having a mass of 1200-2000g (42.24-70.4oz), a body length of 55-58cm (21.65-22.83in), and a wingspan of 145-170cm (57.09-66.93in).  In general, females are around 20% heavier than males and have a wingspan that is 5-10% longer.  Also, ospreys found in tropical and subtropical regions tend to be smaller than those from higher latitudes.  Ospreys have a white underside with a dark brown back.  They also have a characteristic dark strip across their eyes and mottled necklace.  Their feet are pale-blue or grey and have barbs on their feet to maintain a better grip on their food.

Ospreys are distributed throughout all of the continents excluding for Antarctica and can be found around shallow bodies of water that have a lot of fish.  Such bodies of water include salt marsh, mangrove and cypress swamps, lakes, bogs, reservoirs, or rivers.  The osprey’s diet consists almost primarily of fish.  In fact, over 99% of their diet is fish. 

One key element of Osprey’s behavior can be seen when they are hunting for fish.  Instead of hunting from a perch like other birds of prey, Osprey flap and glide 10 to 40 m above the surface of the water.  When they spot a fish, they dive down head-first, raking their talons forward at the last possible second to catch their prey.  They are successful 24-74% of their dives.  Also, once and Osprey has captured a fish, it will adjust it in its talons with the head facing forward to make it more aerodynamic.

photo M. Noonan

Osprey can be either migratory or sedentary.  Those that are sedentary breed and winter in the same location.  Courtship often centers on food and complex aerial patterns.  An osprey will typically lay around three eggs, none hatching at the same time.  The first will hatch a few days early and that chick will often bully the others for food.  Incubation is 32 to 59 days and they stay in the nest for 7 to 17 weeks.