Osprey

Pandion haliaetus

Background

In the 1940s, the coastal zone between New York City and Boston supported an estimated 1,000 active osprey nests. However, development of coastal marshes and eggshell thinning caused by contamination from pesticides like DDT reduced this number to 150 nests by 1969. In 1974, there was an all-time low of 9 active nests in Connecticut. The banning of DDT in the United States in the 1970s, restrictions on the use of other pesticides, and efforts to build nesting platforms have prompted a steady recovery of osprey populations.

It is not unusual to see ospreys along Connecticut's coast and rivers. While the numbers are cause for optimism, the birds are still sensitive to environmental contaminants and food availability. Therefore, careful monitoring of the osprey population continues to be important.

Range

Ospreys are found almost worldwide. Their nesting range in North America includes coastal areas and large inland lakes. These birds then overwinter from Florida to northern coastal Mexico and south to northern South America.

Description

The osprey is a large hawk distinguished in flight by its white underparts and the distinctive crook formed by its long, narrow wings. Adults are brown to brownish black above with brownish-black marks on the wings and buff to brown speckling on the breast. The head is white with a dark crown and there is a wide, dark brown stripe extending through the eye down the cheek. Both sexes are similar in appearance, although the female is larger. Full adult plumage is achieved at 18 months. Juvenile ospreys strongly resemble the adults, except that the brown feathers of the upper body are tipped buff-white, and the streaking on the breast and crown tends to be heavier. The eye color changes from brown to yellow as juveniles mature.

Habitat and diet

Ospreys can be found along coastal marshes, lakes, and rivers. Their diet consists of almost entirely fish.

Life history

Ospreys return to Connecticut from their southern wintering grounds in late March. They usually choose nest sites near or over water but will travel several miles from the nest to seek food. Preferred natural nest sites are the tops of dead trees (snags). However, they adapt to available sites and have been known to nest on top of duck blinds, channel markers, roots of upturned trees, chimneys, school buildings, cell phone towers, and utility poles.

Ospreys readily use artificial nest platforms, and wildlife managers encourage the use of such platforms in areas where there are few natural nest sites. They do not confine themselves to sticks when building their large nests; seaweed, bones, driftwood, cornstalks and trash from nearby beaches and marshes may also be included.

Osprey pairs usually return to the same nest site and add new nest materials to the old nest each year. An average of three eggs is laid in April; incubation begins with the first egg laid. Eggs are white to pink or cinnamon and heavily blotched with dark brown. Adults are protective of the nest site and may exhibit aggressive behavior at the approach of a potential intruder.

The month-long incubation is usually completed by the female, who is fed by the male during this time. About two months after hatching, young osprey take their first flight. After fledging, the young remain with the parents for up to 2 months, and at the wintering grounds for 2 to 3 years until they return to the north to make their first breeding attempt.

Interesting facts

The osprey, also known as the "fish hawk,” feeds almost exclusively on fresh fish. It can capture a fish weighing up to 4 pounds. The toes of the osprey reflect a unique adaptation to its feeding habits; the lower surface of the toes is covered with spicules (short, spikelike protrusions) which guarantee a firm grip on any fish caught. In addition, ospreys, like owls, have a reversible outer toe, enabling them to grasp their prey with two toes in back and two toes in front. The osprey's plumage is compact, an attribute which helps blunt the impact and reduces wetting when it plunges into the water while fishing. After prey is captured, it is carried headfirst in flight to reduce air resistance.

Human activities, like littering, encourage the presence of predators, such as raccoons and gulls, that can take the eggs or young.

Discarded plastic is particularly dangerous. Litter along the shoreline, especially, monofilament fishing line, balloons with ribbons, plastic six-pack yokes, and bird netting, can get tangled around a bird’s talons and spicules on its feet, causing serious injury and death.

Human disturbances also affect nesting success by keeping adults off the nest, thus preventing them from attending young. Disturbance of ospreys is prohibited under the Federal Migratory Bird Treaty Act of 1918 and the Connecticut General Statutes Section 26-92.

Conservation concerns

Over time, osprey conservation efforts in Connecticut have proven remarkably successful, leading to a significant rebound in the state’s population. Once severely threatened by the use of DDT and other pesticides, the comeback for these fish-eating raptors can be attributed to several factors, such as habitat protection, nest monitoring, and environmental regulations. Organizations such as the Connecticut Audubon Society and the CT DEEP Wildlife Division have played key roles in tracking osprey nests, maintaining platforms, and engaging the public in population surveys.

Connecticut’s ban on the use of harmful pesticides, alongside efforts to clean up waterways and protect coastal habitats, has provided ospreys with a healthier environment for breeding and raising their young.

Today, thanks to these initiatives, the state’s osprey population is flourishing, making the species a symbol of successful wildlife conservation in the state.

How you can help ospreys

• Keep your distance from osprey nesting platforms during the nesting season to avoid causing disturbance to the birds. People and/or their pets should remain at a distance of at least 300 feet from an osprey nest.
• When visiting coastal areas and beaches, dispose of all litter in appropriate waste containers. Use monofilament fishing line recycling containers to dispose of waste fishing line.
• DO NOT release helium balloons into the environment. Balloons and their ribbons fall back to the ground as trash. Those released inland often make their way to coastal areas before falling to the ground.
• Volunteer with the Connecticut Audubon Society's Osprey Nation to monitor osprey nests during the nesting season. The final results are reported to the Wildlife Division. Send an email to osprey@ctaudubon.org to find out how you can get involved.
• If you have appropriate habitat on your property for ospreys, erect a nesting platform. For sites below the Coastal Jurisdiction Line, you must apply for a free general permit through DEEP’s Coastal Permit Program.

The Wildlife Informational Series is partially funded by the Federal Wildlife Restoration - Pittman-Robertson (P-R) Program. The P-R Program provides funding through an excise tax on the sale of sporting firearms, ammunition, and archery equipment.

Content last updated in July 2026.