The Osprey, sometimes referred to as the fish eagle, is one of the most well-known raptors in the New York Harbor area. These birds are easily recognizable and fascinating to observe, with wing spans of about 5 feet, brown and white patterned feathers and large, incredibly strong talons.
Fish make up 99% of Ospreys’ diet and are most frequently sighted near bodies of water–rivers, lakes, and coastal areas. One of the most prevalent birds of prey, they are found on every continent except Antarctica. Ospreys are migratory birds and travel great distances between the summer breeding areas in North America and their wintering grounds in Central and South America.
Once a major feature in the Northeast region’s ecosystem, populations on the Atlantic coast plummeted in the 1950s and 1960s due to use of DDT, a pesticide that weakened the shells of Osprey eggs to the point that chicks could not survive. The severity of the threat was compounded by the birds’ position at the top of the food chain due to the bioaccumulation process–the chemical would continue to build up in Osprey’s bodies as they consumed prey that carried DDT. After the ban of DDT in 1972, the species population has seen a drastic recovery, and indeed in 2010 there were 12 breeding pairs at Jamaica Bay alone.
Ospreys build large nests of sticks and driftwood in conspicuous locations including telephone poles, channel markers and other high platforms near bodies of water. In many areas nesting platforms are built specifically to encourage local breeding. The birds acclimate to humans very quickly, and often can be found nesting very close to developed areas.
In the late spring and throughout the summer, breeding pairs of Osprey will incubate and raise their chicks. Laying typical clutches of one to four white and brown speckled eggs, both the male and female will incubate and feed the chicks. The eggs hatch over the course of multiple days, which results in older chicks that are physically stronger and able to monopolize the food brought by the parents. If food is scarce, the younger chicks often do not survive.
Ospreys hunt by slowly flying and circling over shallow water to seek out prey. When they spot their catch they may hover briefly prior to making the dive, feet first, to snatch the fish. It is not unusual to see the catch in the bird’s talons as the bird carries it back to its nest. Indeed, Ospreys are one of only two raptor species with a reversible toe, allowing them to form a pincer of sorts to grasp their slippery prey.
Gateway National Recreation Area has active Osprey nesting pairs at all three of its units – Staten Island, Sandy Hook, and Jamaica Bay. While these birds are known to leave the park every fall for the southern migration, exact details and destinations are not known. GPS tracking of an adult Osprey will provide an in depth look at the species’ life history, and offer crucial insight into our understanding of these fascinating birds.