ODNR Division of Wildlife - A to Z Species Guide - Osprey

Osprey

osprey

Ospreys were once a common sight throughout North America, but habitat destruction, persecution and the wide-spread use of chemical pesticides such as DDT during the middle of the twentieth century led to a drastic population decline.

Ohio's osprey reintroduction program is a huge success. Originally started in 1996, the program had a goal of 20 nesting pairs of ospreys by 2010. That goal was achieved in 2003; seven years ahead of schedule.


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Osprey
Pandion haliaetus

At-a-Glance

• Classification: Bird (Raptor)

• Mating: monogamous (generally)

• Peak Breeding Activity: Breeding begins between December and March in non-migratory populations. In migratory populations, breeding begins in April or May.

• Diet: Mostly fish, occasionally small mammals, birds, and carrion.

• Habitat: River corridors, lake edges

• Size: Length: 25 inches; Weight: 3 lbs; Wingspan: 4-5 ft
Description
Ospreys 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 bottoms of an osprey's feet are also specially adapted for gripping and carrying fish, as they are covered with short, sharp spines.

Habitat and Habits
Ospreys live almost anywhere where there are safe nest sites and shallow water with abundant fish. They are spectacular birds to watch, particularly when they are feeding. Hovering high above a lake, river, or pond, these large white and dark-brown birds search for fish cruising near the surface. Spotting one, they quickly fold their wings and dive, hitting the water talons first. Ospreys are the only species of bird that combines this plunge-diving feeding behavior with a raptorial foot--a foot with a flexible toe that can be moved to grip a slippery fish with two toes pointing forward and two back. Once airborne again, the bird manipulates the struggling fish so as to carry it head first, making it more streamlined in flight. The osprey also removes any water from its feathers as it flies by shaking itself, much like a dog.

Reproduction and Care of the Young
Once mated, the pair will build a stick nest lined with grasses either over or near water. Ospreys use the same nest year after year, which sometimes grows to be as much as five feet wide and several feet deep. Ideal nest locations consist of an open, high platform near a good supply of fish. Usually three or four eggs are laid by ospreys and both parents help with the chore of incubation. The eggs are white with brown splotches and about the size of a large domestic hen's egg. They begin hatching in about 38 days, usually in the order they were laid. This means that the last young to hatch are smaller and several days behind their siblings in development. This is a significant disadvantage for the younger birds, thus usually only two chicks per nest survive to fledging.