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Ospreys have returned to Massachusetts! These migratory fish-eating raptors returned in March to begin their courtship and nest building. An osprey pair that had previously nested comes back to an old nesting sites – a place with good visibility, safe from most predators. There, they build a large nest out of sticks. Males collect the sticks, while females collect the lining. Over the years, the size of nest can grow – up to 10 feet in diameter – because the birds add more each year.
In 1925, ornithologist Edward Howe Forbush wrote of the persistence of these nest builders:
A good friend of mine bought a farm in Touisset [Swansea] … [W]hen the family moved in they found a great nest on the top of the kitchen chimney with a pair of Ospreys in full and complete possession of the premises. Before starting a fire in the range it became necessary to remove that nest … Immediately the birds began to rebuild the nest. They brought large sticks and placed them across the chimney, and to hold them down they brought clods and stones. Destruction of their domicile did not discourage them in the least. At last in self-defense my friend was obliged to shoot the female. The male did not mourn long but flew away and in a few hours was back again with another mate (“just like a man,” the good wife said), and the pair, having first reconnoitered the place, decided to recommence building. When they had finished, they had filled up that chimney from bottom to top with sticks, stones and rubbish, so that it became necessary to either destroy those birds or give up the house to them.
Besides nesting in kitchen chimneys, you might spot an osprey nest on a light post, telephone pole, cellphone tower, a channel marker, a humanmade platform, in a tree or on a cliff. In the nest, the female lays about two eggs. The eggs hatch in about 40 days. Both parents carry fish back to the nest for the chicks to eat. The adults put one foot in front of the other and carry each fish head forward to reduce wind resistance as they fly.
As the chicks grow, they begin to look like their parents, except they have orange eyes rather than an adult’s yellow eyes. It takes almost two months for the young birds to become flyers. They catch their first fish two to eight weeks later.
After learning to fly, youngsters stay near the nest until fall migration. In the fall, when cold water causes fish to move south, osprey follow. They fly near the coast and over the Caribbean to South America.
According to Mass Audubon, osprey populations in Massachusetts in the colonial era declined because colonists chopped down trees to create farms. In a few places, farmers realized that the fierce osprey drove hawks away from farmlands, protecting young chickens. According to Forbush, while osprey “are incubating their eggs and rearing their young, they will not allow other hawks in the vicinity of their nests, and, as the young chickens are allowed to run at large at that season, the Ospreys protect the chickens from the forays of other hawks.”
Some farmers even erected poles topped by wagon wheels to serve as osprey nest platforms. For similar reasons, even today smaller birds build nests in or near osprey nests. They know the ospreys will keep the hawks at bay.
Scientists knew of only 11 pairs of nesting ospreys in Massachusetts by 1964. Pesticides such as DDT caused thinning and breaking of osprey eggshells. Without new chicks, the population declined. Because ospreys nest in visible locations where scientists can easily monitor them, their egg dilemma helped scientists understand the harmful effects of the chemical; because of this knowledge, lawmakers banned it in 1972. Since then, osprey numbers have increased. (The construction of osprey-nesting platforms has boosted their survival rates, too.) In 2024, there were about 90 breeding pairs of ospreys in northeastern Massachusetts, 11 percent more than in 2023. These birds built 61 nests on nest platforms last year, and 13 on channel markers, 10 on light poles or towers, three in trees and three on hunting blinds.
Ospreys have impressive hunting skills. They can see a fish underwater even when they are 100 feet above it. They hover above the water for several seconds, then plunge at speeds up to 80 miles per hour, talons first, into the water to seize the fish. Unlike other raptors, osprey will submerge to capture a fish. As they resurface, they rest for a moment, secure their grip and take to the air, shaking the water from their feathers as they fly. Most of the fish they grab are about half a pound, but sometimes they may stick their talons into a fish that is too large to lift. If they cannot retract their talons, they may be pulled under and drowned by the fish.
Ospreys are extraordinarily accurate hunters. According to the Cornell Lab of Ornithology, they catch fish on about 25 percent of their dives. On average, it takes them just 12 minutes to catch a fish. Unlike other hawks, ospreys have a reversible outer toe. This allows them to hold a fish with two toes in front and two toes in back. Their toes have barbed pads and a sandpaperlike texture that helps them hold squirming prey.
William Brewster wrote in 1906 that the osprey, then called the fish hawk, was seen in Cambridge during fall migrations:
It used to occur most numerously in autumn, at Fresh Pond where, during the month of September, thirty or forty years ago, one or two of the big, eagle-like birds were almost constantly present. In those days the untrimmed woods which came to the water’s edge along the shores of the Tudor estate, at Strawberry Hill, and at Hemlock Point, afforded plenty of dead stubs or branches on which the Fish Hawks and Kingfishers loved to perch. Both birds found food in abundance here, for the pond then swarmed with alewives and other fish. Since the alewives have been shut out by the filling in of the natural outlet, the Fish Hawks have visited Fresh Pond much less often than formerly.
To observe nesting ospreys, you can do so without even leaving your house: Several osprey cams have been installed throughout the state. Most females lay eggs in April. They incubate the eggs through May. In June, the eggs hatch. The first flight attempts should occur in July. The nearest cam is at Belle Isle marsh. But there are others at Oxford, Gloucester and Falmouth.
Reader photo
S. Weaver spotted this indigo bunting in Franklin County, Georgia, on April 22.
Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name and the general location where the photo was taken.
Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.
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