Osprey Comeback

We all love a story with a happy ending. Amidst the gloom and doom of recent environmental news comes a soaring story of success and an icon for the ages: the osprey, returned from near extinction. The uplifting tale (or in this case, tail) of the osprey’s recovery is one of a hero’s success, and what could be better? Especially when the star is a bird, and nature wins. Yes, nature does sometimes win.

Flying like their life depends upon it (which it does), a small army of these raptors is coming our way as you read this. Winging their way north, ospreys are returning to Martha’s Vineyard and the rest of the East Coast from their winter homes in Central and South America. How they get here — and even the fact that they get here at all — is as impressive as their ancestors’ fight for survival.

Heroic tales often start with “Once upon a time,” and this one is no different.   

Once upon a time, ospreys were a rare sight in the skies over Martha’s Vineyard. The 1959 book, Birds of Martha’s Vineyard (now out of print), by Ludlow Griscom and Guy Emerson, documented only a few nests on-Island. They described the bird as a “regular transient in small numbers” in the years between 1913 and 1941.

By the 1950s, a few osprey nesting efforts were observed and recorded, with each pair fledging two to three young each year. However, despite these successes, the Island population was not increasing overall. 

This mystery would soon be solved. Griscom and Emerson also documented a pair of ospreys that had “built a nest on telephone pole cross-pieces at the dyke on Chappaquiddick in 1954,” which was “demolished by telephone workers — Cape Pogue lines were affected.” 

This important clue highlighted the challenge for ospreys of finding suitable nesting areas on an island where trees were diminutive and slight. These indomitable birds faced a new problem, after their population had earlier in the century came back from the brink of extinction.

DDT Disaster

Ospreys, which have four subspecies across the globe, were once common and abundant worldwide. Found everywhere except Antarctica, these prolific birds had fallen on hard times and suffered a dramatic decline in the mid-twentieth century. As in most fairy tales, there was a villain to blame.

This evil was not human (even if created by humans), but chemical. It was called Dichlorodiphenyltrichloroethane, known more commonly as DDT. DDT was first synthesized in 1874, though its potency as an insecticide wasn’t known until 1939. Once that property was discovered, this chemical was quickly put to use during World War II to kill insects that caused diseases such as malaria and typhus. It was so effective and important, and saved so many people's lives, that the man who developed DDT as an insecticide, Swiss scientist Paul Hermann Müller, was awarded a Nobel Prize.

After the war, DDT became popular as an effective agricultural and household pesticide and was used widely nationwide. The Vineyard had less exposure than most parts of the country to DDT, not because we knew better, but due to a more practical concern — cost. 

According to Dr. Rob Bierregaard, ornithologist and osprey expert, who has spent a lifetime studying this iconic bird, Martha’s Vineyard stopped using DDT in 1958 because of financial considerations. He explained, “it was too expensive for the helicopters to bring and spray the chemicals.” Frugality worked in our favor.

Although there were early concerns about the effects of DDT and other organochlorines (such as dieldrin) on nontargeted species, it took environmentalist and author Rachel Carson's book Silent Spring to widely expose the depth of the chemical’s wildlife and human toxicity. Carson’s groundbreaking work led to the banning of these chemicals in 1972. 

But locals on Martha's Vineyard noted that even here, DDT had had an impact. Ornithologist, bird bander, guide, and Vineyard author Mabel Gillespie, in her 1976 Island book, Where the Birds Are (see our reading list at the end), matter-of-factly conceded that “in recent years oceanic fish have ingested sufficient quantities of DDT and mercury to affect fish-eating birds like eagle and osprey. It is well known that both of these species are in danger of extinction.”

As Gillespie noted, an after-effect of DDT’s insect apocalypse was its contamination of the food web, as the chemical bioaccumulated in the habitats and bodies of wildlife. Starting with insects and relentlessly ascending the food web, the consumption of chemical-laden prey increased toxicity with every contaminated meal consumed. As these compounds were fat-soluble and not readily excreted, they were stored in animals' fatty tissues, and, over time, became concentrated in the bodies of all creatures. (Currently, we’re seeing the same phenomenon played out with microplastics and mercury in fish species.)

For ospreys, the arithmetic was brutal: the more fish eaten, the more DDT ingested. And it wasn’t something anyone would want to ingest. DDT interfered with the bird’s uptake of calcium, which led to thinner and more brittle eggs. These decidedly delicate eggs were often crushed under the weight of the incubating bird, resulting in the incubating mother killing her potential offspring. 

With limitations on the spraying of DDT, the few osprey pairs present on the Island had an advantage over the off-island birds whose populations struggled along in places where more chemicals were used. By the early 1970s, there were two nesting osprey pairs documented on-Island when Dr. Bierregaard began his studies here, and year after year those birds were successfully fledging three to four young. Island birds were destined to succeed, but they didn’t do it alone. 

The Godfather of the Island Ospreys

Even with Martha’s Vineyard birds’ high reproductive rate, the number of pairs was not increasing locally in the early 1970s, while paradoxically, in other areas in New England, osprey numbers were rising. This conundrum was solved by Gus Ben David, a naturalist and the first director of Mass Audubon’s Felix Neck Wildlife Sanctuary, who would become known as the Godfather of the Island Osprey for his efforts.

Ben David, through his work with Mass Audubon, would become the species’ Island hero and lead the charge to bring ospreys back to our skies and beyond. As Felix Neck’s second director, I now continue the work Ben David began. Having learned that young ospreys were setting up their nests on electrical transformers, and those nests were being removed by Commonwealth Electric (the regional power company at the time), Ben David developed a prototype and began to install a nesting alternative: tall poles with supportive platforms. The birds took to them right away.

To understand the choice of nesting locations, one must get into the head of this beautiful bird. We can now come home to the place where this story roosts.

What Makes a Good Osprey Home

Ospreys are fishing birds, and want to nest near water. They select a high perch that has good visibility and is protected from predators like raccoons. A sturdy structure is also a must, since osprey nests can weigh up to 400 pounds.  

Trees are where ospreys would normally nest, though they will readily adopt other sturdy, high places, such as chimneys, sailboat masts, and light poles. Island trees are not very tall and not always strong enough to hold the birds’ massive nests. Last summer, a tree nest at Felix Neck was found on the ground, the eggs in it destroyed, after its supporting branches broke in a nor’easter.

An osprey will try to rebuild its nest if it is knocked down by wind, other territorial birds, or even humans. In the past, the nest on a light pole at Veterans' Memorial Park in Vineyard Haven was removed, only to reappear, having been rebuilt by a persistent osprey. This back-and-forth — ospreys constructing their nests, the power company knocking them down, ospreys rebuilding — can continue ad infinitum through the season. However, there eventually comes a time when it can get too late in the season for egg laying. Ospreys must breed and fledge young before their fall migration. 

Osprey nests are a wonder unto themselves. Their considerable size is only one of the factors that makes them a sight to behold. They are built from a bevy of materials, incorporating twigs and sticks of all sizes, bark, grass, seaweed, and — often — an intriguing collection of non-natural items. Birdwatchers across the Island have reported seeing nests that contained items including rope and line, fishing nets, boots, gloves, and plastic objects.

With their penchant for collection, ospreys are guilty of “autolycism” — a term inspired by the character Autolycus from Shakespeare’s The Winter’s Tale, who was described as a “snapper-up of unconsidered trifles.” The term, in the case of ospreys, describes the birds’ inclination to use other animals' (and people’s) unwanted stuff in nest construction. Author John Steinbeck claimed to have found an osprey nest that included three shirts, a bath towel, and a garden rake. Nest construction is a science, but also most definitely an art. 

Getting back to history and Gus Ben David’s 1970s nesting poles: Initially helped by the power company, which didn’t want the birds nesting on transformers, Ben David began to put up safe, secure poles with platforms, figuring that an alternative to utility poles was the easiest option for adaptation. 

Ben David installed the first pole at Mink Meadows in 1971, followed by eight more through the 1970s at sites including Tashmoo, the State Forest, Seven Gates Farm, Chappaquiddick, Squibnocket, and Felix Neck (which got two). Today, there are many more; as efforts, awareness, and funds were raised, so were more poles.

Saving a species shouldn’t be a lonely endeavor — it never is — and Ben David was joined by a bevy of besties, birders, and builders who helped install a plethora of poles. Throughout the 1970s and 1980s, just prior to my years working as an education coordinator for The Trustees of Reservations, I was heartened to see that the osprey population was doubling every five years, plateauing for a time in the 1990s and 2000s before continuing to climb.  

By the Numbers: Vineyard Ospreys Today

Over the years, more than 300 nesting platforms have been built, though many have come and gone with weather, rot, and collapse. The Vineyard efforts have contributed to the recovery of the osprey in southern New England and — thanks to Ben David, his crew, volunteers, monitors, and other osprey-lovers — we see hundreds of ospreys in Island skies. Ben David passed away last year, though many of us were lucky enough to have assisted him in the construction of a pole or two. The work will go on. A beautiful osprey sculpture can now be found at Sunset Lake in Oak Bluffs, a tribute to this beloved bird and this man’s effort to save it.

To follow the species' progress, the many people who have, and had, a stake in this story — Gus Ben David, Dr. Bierregaard, and Mass Audubon staff and volunteers, among others — have taken annual censuses to monitor the osprey’s Island progress. The 2025 census revealed impressive stats. People observed approximately 145 (potentially breeding) pairs and visited over 185 sites to determine if birds were successfully nesting. And succeed they did, with 141 fledglings (young birds) that survived from at least 84 nests — a very good reproductive effort, indeed. 

Sadly, ospreys from the Chesapeake to Massachusetts did not do as well as Vineyard birds this past year. Their poor reproductive success might be attributed to the population collapse of a favorite fish, menhaden. Our local birds aren’t exclusively dependent on menhaden and can fish the Great Ponds and Cape Poge and Katama Bays to find other species that are plentiful.

Built to Fish

Ospreys’ fishing prowess would make any angler envious. Sometimes called “fish hawks,” ospreys eat fish almost exclusively. They do so with a spectacular dive from up to 90 feet high. Head- and talon-first, they plunge into the water, traveling as far as three feet below the surface to grab their prey. Then they re-emerge, lift their wings above water, and take off. With a very large fish, ospreys can struggle at this stage, and there have even been reports of birds drowning from a massive catch, too heavy to allow for liftoff. 

Ospreys have evolved to be hunting machines. Start with their talons: ospreys have four toes on each foot. When at rest, they hold three toes in the front and one in the back.  However, they can swivel their third top toe so that there are two on the top and two on the bottom. This “zygodactyl” arrangement (think of an X orientation) helps them grasp and hold fish. Their talons are covered with short, stiff spikes. They don’t let go (hence the occasional drownings when gripping overly large fish). When flying, ospreys hold their fish in line with their bodies in order to reduce wind resistance. Even eagles have not thought of this strategy.

Another helpful physical characteristic is the ospreys’ nostrils, which close when they dive. Nature thinks of everything. Add to that their oily feathers, which repel water, and you have “a miracle of evolution,” as Hooper in Jaws said when speaking about another wild hunter. Not to mention the birds’ arched wings, which propel them from the water and have an aerodynamic form that provides for efficient flight and speedy diving.

Ospreys know, like many of us, that food is love, and a male brings a female fish gifts to woo her. This is called courtship feeding, and those nuptial gifts can assure his success or failure. If he doesn’t provide enough food, the female will be less receptive to mating, and may even beg him or other males for food. During courtship, the bestowing of fish can be preceded by an aerial display, or a sky dance, with the male loudly calling while engaging in undulating flight. “She hers, he his, pursuing,” as Walt Whitman wrote in The Dalliance of Eagles, even if here we speak of osprey.

If he gets the girl, so to speak, the male osprey’s fishing will need to increase once his mate lays eggs. Incubation is constant — and required: the eggs cannot be allowed to grow cold. Although eggs can be tended by either bird, the female spends the majority of time on the nest, relying on her mate to bring her meals. A clutch of three or four young, plus mom and dad, will need three to seven fish per day.

Location, Location, Location 

Ospreys couple only during the breeding season. Those who have lost their partners will find new ones when it’s time to breed again. The couples, perhaps (or perhaps not) surprisingly to us, migrate and winter separately, and rendezvous by some miracle of instinct at their nest site annually. 

While people like to say that ospreys mate for life, it is not each other that drives their desire, but rather location, location, location. Loyalty is to the nest site first and foremost, and if both birds return to their breeding nest, they will be together. However, another bird can usurp either partner if one doesn’t return or if he or she is a stronger bird and takes over a nest site.

When osprey couples reunite and food is plentiful, their mating activities can be frequent. In one 45-day study, scientists (or voyeurs) documented 288 pair copulations.

Vineyard ospreys generally arrive on the Island from late March into April. An early documented date of March 14 for their arrival is unusual, though with climate change this might become more normal. Early reports come in every year, but often are not confirmed or could be a case of misidentification (such as a red-tailed hawk resting on an osprey nest). Distinguish the two by their body orientation: red-tailed hawks hold their body vertically, while ospreys more often than not have a horizontal stance.

After the pairs reengage, settle in, and mate, the female lays up to four eggs, which  are incubated for five to six weeks. The young that emerge (not all eggs are viable) are semi-precocial, meaning that the chicks can move around, are down-covered, and have eyes that are open. Newly hatched osprey cannot fly and must rely on their parents for their first few months, after which they will be ready to fledge (develop wing feathers that are adequate for flight) and care for themselves.

Those fledged ospreys take some time to learn to fish successfully. Early on, these youngsters might only have a 5% success rate in catching fish, whereas adults catch fish on more than 90% of their attempts. Perhaps that is why you sometimes hear young birds crying for their parents to feed them when they should be able to fish for themselves.

You can watch all of these antics at your local osprey nest. Even easier is observing the Felix Neck pair on the Sanctuary’s Osprey Cam, or other birds on one of the many osprey cams that can be found online. Heed this warning: watching these birds can become an obsession; it gets very hard to tear yourself away from these fascinating flyers.

While the Felix Neck birds may be engrossing, there have been other famous ospreys. There was Snowy, a bird that in 2015 flew 400 miles in a 24-hour-a-day migration marathon and covered the distance from Cuba to Cape Cod in six days.  We know about Snowy because of Dr. Bierregaard’s 20 years of radiotelemetry work to track osprey migration.

Or, learn about Belle, immortalized by Dr. Bierregaard in his children’s book Belle’s Journey. Bierregaard shared that Belle was his favorite osprey, having flown across the Atlantic from Martha’s Vineyard to the Bahamas in a non-stop trip of almost 1,200 miles. The bird’s fictional adventures included challenges that real birds can face. Belle the bird has a small role in another book, author Belle Burden’s (the bird’s namesake) new book, Strangers: A Memoir of Marriage.

There is very little to suggest that ospreys will now do anything other than thrive. While the occasional Bald Eagle will try to usurp their nests, ospreys have, up to now, consistently chased them away. Ospreys have beaten the odds more than once and have a dedicated following of fans that love and cheer, if not work, for their survival. 

These birds, along with those of us who love them, will have their happily ever after.

Timeline