2014-05-08 / Nature

Osprey Return for the Season

By Jack Kelly


The average adult Osprey has a wingspan of between 64 and 71 inches. This male Osprey created a spectacular flash when he emerged from the Gooseneck Cove salt marshes. (Photo by Jack Kelly) The average adult Osprey has a wingspan of between 64 and 71 inches. This male Osprey created a spectacular flash when he emerged from the Gooseneck Cove salt marshes. (Photo by Jack Kelly) Of all North American birds of prey, one of the most captivating species may be the Osprey. This migratory raptor was on the verge of extinction in the early 1970s due to eggshell thinning and premature hatching, both of which were directly linked to the pesticide DDT. The organochlorine chemicals in the pesticide caused a genetic change in the birds’ calcium metabolism. Since the Environmental Protection Agency’s ban of DDT in 1972, the species has enjoyed a long but steady recovery. Due in large part to the efforts of conservationists, biologists, ornithologists, and volunteers, the Osprey is now fairly plentiful throughout the United States and Canada.

Locally, an Osprey Recovery Monitoring Program was begun by the Rhode Island Department of Environmental Management in 1978. The project revealed that there were only 13 active nests in the state with only 15 fledglings. Over time, the effects of the pesticides wore off as new generations were hatched and matured. In 2010, the Audubon Society of Rhode Island assumed management of the monitoring efforts. Through the diligent work of dedicated staff members and volunteers, the organization recorded 98 successful nests and 171 fledglings that year. During the 2013 monitoring program, 94 nests and 164 fledglings were noted.


Jack Kelly, a native Newporter, is a wildlife photographer and nature enthusiast who enjoys sharing his experiences with others. Jack Kelly, a native Newporter, is a wildlife photographer and nature enthusiast who enjoys sharing his experiences with others. Aquidneck Island is home to at least nine nesting sites, with at least one new nest being established each year. As Audubon volunteers since 2010, Mark Anderson and I are entering our fifth season of monitoring nesting sites in the southern region of Newport. We have been watching the Freebody Park/Toppa Field Ospreys since they first established their summer home in 2006. We have met and become friends with many of the folks who live close to the park. The antics and behaviors of the avian visitors delight and thrill their human neighbors, who are very protective of “our birds.”

In the eight seasons prior to 2014, we observed the adults raise 19 chicks to fledgling status and depart the nest for a migration of up to 2,500 miles to wintering grounds in South America. The average life span of the Osprey is 15-20 years and it is estimated that they can register approximately 160,000 migratory miles in a lifetime.

The average adult Osprey has a wingspan of between 64 and 71 inches, a body length of 21-24 inches, and a weight range of 3-3.6 pounds. The female of the breed is larger than the male by almost one-third and has a noticeably thicker neck. Both sexes have dark brown plumage above and white below, and have underwings that are a mottled brown and white. A short, white head crest, dark eyestripe and yellow eyes also distinguish adult birds.

Osprey pairs are lifelong mates Although they spend the off-season separated, they reunite at their nest in early spring, usually arriving a day or two apart. The couple immediately begin a two-week courtship and breeding ritual that includes repairing their nest and fortifying their bond. The male performs a “sky dance,” also called the “fish flight,” as he dangles his legs while grasping a stick or fish in his talons and hovers approximately 600 feet above the nest. In a series of shallow swoops, he descends in an undulating motion while emitting repeated calls to his mate. This display may last up to 10 minutes.

Establishing a nest is a major part of a newly mated pair’s breeding ritual and their future seasons together. The male will usually choose the site and brings sticks to the female who places them in an interlocking pattern. They are lined with bark, sod, grasses, algae and bits of man-made materials such as cloth or plastic shopping bags. New nests usually measure about 2.5 feet in diameter and are initially 3-6 inches deep. During their long life spans, a pair can add enough material to expand the nest to 3-6 feet in diameter and 10- 13 feet deep, weighing hundreds of pounds.

The female will lay a clutch of 1-4 eggs over a 3-5 day period. They are cream to pinkish-cinnamon in color and wreathed and spotted with reddish-brown tints. Both adult birds share incubation duties that can last for 36-42 days. The down-covered chicks will hatch days apart, with open eyes capabile of limited motion. They require vast amounts of food over an estimated 50-55 day growing period before they reach fledgling status.

Ospreys fly on bent, gull-like wings with a “rowing motion” and are the only raptors that eat live fish exclusively. The raptor hunts by hovering over the shallow waters of ocean coastlines, ponds, lakes, rivers, reservoirs, swamps and marshes. Capable of diving three feet deep into water, it will seize fish with open talons lined with retractable barbs known as spicules. Rising from the water, the bird secures its prey and turns the fish head first to maintain aerodynamics.

At the present time the pair at Toppa Field are incubating eggs that may begin hatching in a week to 10 days. The neighbors are curious to see how many young birds will appear.

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