Ospreys May Be in Trouble Again

Photo: Osprey and its young at the Belle Haven Marina platform nest on June 18, 2025, Glenda C. Booth

Glenda C. Booth

Reprinted by permission from the Connection Newspapers

Osprey and its young at the Belle Haven Marina platform nest on June 18, 2025, Glenda C. Booth

They usually grow up and leave in July — Ospreys, 22-inch-tall, brown and white raptors with a 65-inch wingspan, birds that nest and raise their young near open water in northern Virginia from March to August. 

Many people are intrigued watching them dive feet first to catch fish with their sharp talons, take them to the nest, rip them apart and eat and feed them to their young. They build nests, a jumble of sticks, or refurbish old nests every spring, in northern Virginia generally along or near the Potomac and Occoquan Rivers, in trees, on platforms, duck blinds, poles and channel markers. 

This year has brought some troubling signs for these impressive birds.

Ospreys in Dyke Marsh

For many years, Ospreys have returned to Dyke Marsh in March and a pair has built a nest and raised their young on a platform at the Belle Haven Marina on the northern edge of Dyke Marsh. This year, the pair had two chicks, but around the end of June, one had perished. 

Larry Cartwright, who has conducted a breeding bird survey in Dyke Marsh since 1994, reported on June 30, “The female was feeding the survivor today and the nestling was taking the offered food quite readily but looks a little stunted in development. The bird just sat there after eating with a quick break to jet a nice stream of excrement over the side of the nest, but little additional movement.” His July 6 report was more encouraging: “The youngster was more active today, standing up in the nest and flapping its wings for the first time. Hopefully, fledging will occur within the next two weeks.”

Ospreys at Porto Vecchio

For over a decade, Osprey pairs have successfully raised young in nests on two platforms near Porto Vecchio condominiums next to Hunting Cove at the confluence of the Potomac River and Hunting Creek. Three chicks from the northeast nest and two chicks on the southeast nest born this spring are now flying. 

Several Porto Vecchio residents have had to come to the birds’ rescue over the years. Ospreys from these nests have died from fishing line entanglements at least twice in the past. Last summer, two residents rescued a chick from fishing line and this year, rescued two more chicks, one after falling from the nest and the second from twine wrapped around its wing.

More Ospreys

Jay Spiegel has had an Osprey camera on a Little Hunting Creek nest behind his house for several years. This year a pair had two chicks, but Spiegel reports that around June 23, the chicks disappeared. He does not know why.

For several years, a pair has nested atop a light pole over Walt Whitman Middle School’s softball field. Observers saw an Osprey there this year several times, but no one confirmed nestlings.

Challenges for Ospreys

Ospreys appear to be having a difficult year. Definitive data await final surveys. Local experts point to stressors like a weak shad run this spring on the Potomac, warming waters that affect the timing of fish migration, extreme cold and heat events during the hatchling phase, fewer ideal breeding areas because of ever encroaching development, competition with increasing eagle populations and more severe storms.  

A May 2025 survey of nesting Ospreys on Virginia’s Delmarva Peninsula, led by Dr. Bryan Watts of the College of William and Mary’s Center for Conservation Biology (CCB), reported a 90 percent decline there. He recorded nine pairs in the survey area and said that compared to past surveys from the 1970s and 1980s, “the 2025 survey reveals a nearly complete collapse of the population.” Watts concluded, “The most likely cause of the decline is prey availability. However, no Osprey diet studies have ever been conducted within this site, and we know very little about trends in fish availability.” 

CCB scientists previously reported that in the lower Chesapeake Bay, a silvery fish called Atlantic menhaden are nearly 75 percent of Ospreys’ diet. Some conservationists argue that large-scale, commercial menhaden harvests are depleting menhaden stocks and that government officials should reduce current limits on the number landed or caught.

There have been several efforts in the Virginia General Assembly in recent years to require a comprehensive study of the menhaden population, but those bills have failed. The Chesapeake Bay Foundation’s website says, “Atlantic menhaden are the target of Virginia’s largest commercial fishery, run by a company called Omega Protein, and its affiliates. Typically turned into fishmeal and fish oil products in a process known as ‘reduction fishing,’ the small schooling fish also are a key food for iconic predators like striped bass, bluefish, and Ospreys. All other states have banned the practice of reduction fishing.”

More Osprey Facts

• Ospreys mate for life and usually return to the same nest every spring. They typically incubate one to four eggs for 36 to 42 days. 

• Because they add materials to their nest year after year, a nest can be ten to 13 feet deep, three to six feet across and weigh up to 250 pounds. They may “decorate” their nests with items like shoes, cans, fabric, fast food debris and toys. Ospreys can become entangled in things in the nest, like plastic bags, balloon ribbons and monofilament fishing line.

• Over their 15-to-20-year lifetime, Ospreys may migrate more than 160,000 miles. 

• In the early 1970s, Osprey numbers plummeted and scientists concluded that the eggshells of Ospreys, eagles and other birds were so thin that they broke during incubation and birds failed to hatch. They concluded that the hatching failure was due to pesticides that moved up the food chain. In 1972, the U.S. Environmental Protection Agency banned DDT and populations recovered, until recently. 

EDITOR’S NOTE: For more information about the challenges Ospreys face, see the article about Ospreys and menhaden from the June 2025 Potomac Flier, and watch Joanie Milward’s March 2025 talk, Ospreys in the Chesapeake Bay Watershed.

Ospreys and the Menhaden Question

Photo: Osprey, Lewis Scharpf/Audubon Photography Awards

Evelyn Novins

It’s always a joy when Osprey return to northern Virginia in the spring to breed after their winters in the Southern Hemisphere. Like the Bald Eagle, the bird is a prime example of successful population recovery following the ban of DDT, increasing in Chesapeake Bay from 1,450 pairs in the 1970s to 10,000 nesting pairs today, about ¼ of the population in the United States. So, it’s disheartening to learn of an increase in nest failure in areas of the Chesapeake Bay, reported by both Greg Kearns, senior naturalist for the Patuxent River Park, and Dr. Brian Watts, from the Center for Conservation Biology at William and Mary University. 

Osprey, Kurt Wecker/Audubon Photography Awards

But before we dig into that discussion, let’s review a little information about the Osprey, Pandion haliaetus, sometimes called the fish hawk, seahawk, or fish eagle. It’s a diurnal bird of prey which hovers over water before making spectacular dives for fish. It spots the fish from as far as 150 feet up and begins a forward dive to the water, but it enters with its feet first to grab the prey. Its nostrils close to keep out the water, and a nictitating membrane protects its eyes. The Osprey’s talons have a 6- to 8-inch spread and are equipped with spicules (spiky spines) to grasp its catch securely. Holding the fish head forward as it flies back to the nest, it usually stops along the way to eat the head first, killing the fish and stopping its struggle. It appears that 1 in every 3 or 4 dives is successful.

Osprey traditionally build their nests at the top of tall trees. However, they have become accustomed to and look for man-made platforms which suit them well. They seem to know that their primary predator, racoons, find these structures difficult to raid. However, the great horned owl and the eagle still have access. Ospreys exhibit nest fidelity, returning to the same nest site year after year, especially if they have been successful in raising chicks. First year Osprey often remain on wintering grounds for an extra year before heading north to breed in the area where they were born.

Back to reports of nest failure at high levels in certain areas of the Chesapeake Bay. First, note that a nest productivity rate of 1.15 or greater is required to sustain a population. Greg Kearns, who has been monitoring Osprey along the Patuxent River for 40 years, reports a drop in nest productivity from 1.8 in 2013 to 0.86 in 2024, or 6.57% nest failure in 2013 to 45.07% in 2024. Even higher levels of nest failure were reported in some intervening years: 58.95% in 2017, 60.41% in 2020, and 56.67% in 2023, productivity rates of 0.73, 0.67, and 0.61, respectively. Kearns’ March 18 talk, Ospreys on the Patuxent, a Smithsonian Environmental Research Center presentation and the source of those figures, is still available online free of charge following registration. 

Dr. Watts’s research of Ospreys in the Chesapeake Bay indicates that Osprey feeding in lower salinity areas in the rivers appear to be doing better than those Osprey near the middle of the Bay, the main stem of the Chesapeake with its brackish waters. The diet of river Ospreys consists of gizzard shad and catfish while the diet of Ospreys in the main stem of the Chesapeake is 75% menhaden. 

An Osprey breeding performance map from an article by Dr. Brian Watts shows areas of steep decline.

He reports that mean breeding performance for Osprey pairs nesting within the main stem of the Bay did not meet the productivity rate required for population maintenance. The reproductive rate in this area was 0.51 young/pair in 2024. The cause of nest failure, documented through webcams, nest inspections and necropsies of dead chicks, is starvation. Dr. Watts’s article on poor breeding performance of Chesapeake Bay Osprey is available here. A graphic from his article shows areas reporting steep declines. 

Conservation groups have urged protections to prevent overfishing of menhaden in the Bay, and the fisheries industry has pushed back. Regulation of the industry in this area is by the Virginia Marine Resources Commission in Virginia’s waters, and the Atlantic States Marine Fisheries Commission, which monitors stock assessment. Menhaden spawn in the Atlantic and swim into the mouth of the Bay, with the Bay becoming a menhaden nursery, where they live for several years before returning to the Atlantic to spawn. 

Menhaden is a nutrient-rich fish containing a very high concentration of protein and omega-3 fatty acids. It is also the primary food source for Chesapeake Bay Osprey and striped bass (rockfish), an iconic Chesapeake Bay fish, which is in decline. Humans don’t consume menhaden, but it is a target of the reduction fishery, which reduces it to a protein-rich fish meal, a commodity used in salad dressing, pet food, omega-3 supplements, oils, makeup, pellet food, and other products. 

Conservation and sport fishing organizations argue that the area is being overfished, disrupting its ecological balance and causing the increasing rate of Osprey nest failures and decline in striped bass. The menhaden industry is an important one in Virginia, and it has pushed back. 

In 2024 the Chesapeake Legal Alliance, with the Southern Maryland Recreational Fishing Organization and other organizations, submitted a petition for rulemaking to the Virginia Marine Fisheries Commission urging regulation of menhaden fishing in Chesapeake Bay and the reduction fishery. After receiving 1,325 comments, the Commission decided to take no action. 

Two bills to authorize a three-year study of the ecology, fishery impacts, and economic importance of the Atlantic menhaden population in Virginia’s waters failed in the 2025 General Assembly, HB19, a proposal introduced by Delegate Lee Ware in 2023, and HB2713, introduced by Delegate Paul Milde in 2025. It’s likely that the issue will return in the 2026 session, in January 2026. We all need to support collection of the necessary scientific information to determine how best to balance the needs of conservation and industry. It’s not too early to send a letter to your representative in the General Assembly urging support for a similar bill in 2026.

Osprey Killing a Crow in Alexandria, VA

Photo: Osprey and Crow, Carol Stalun

William Young 

Carol Stalun, who is a skilled and talented nature photographer, took photos of an Osprey killing a crow. This is probably the first incident, documented with photographs, of an Osprey killing a wild bird. 

Carol Stalun

On Saturday, March 6, 2021, Stalun saw an Osprey along the Potomac River in Old Town Alexandria. Stalun was in the area where there is an Osprey nest from previous years on a platform on pilings in the river. She had seen a male Osprey in the same area the previous day (the first one she had seen in 2021), and she was checking to see if he was still there. 

At 8:33 a.m., Stalun saw a male Osprey on a piling not far from the platform with the nest. At first, she thought the Osprey had a fish in his talons. When she looked more closely, she saw that the Osprey had a crow. Fish Crows were mobbing the Osprey, and Stalun assumed from the vocalizations of the other crows and the location on the river that the Osprey's victim was also a Fish Crow. After being harassed by the other crows, the Osprey flew off with the crow in his talons, did a circle, and returned to the piling. He continued to peck at the crow, who was still alive. The Osprey pecked at the crow a bit longer before flying with it to the platform with the nest, dunking the crow in the river along the way. At 8:45 a.m., the Osprey arrived at the nest and dropped the crow into it. Because the nest is deep, the crow was no longer visible after the Osprey dropped it. Stalun had not seen the Osprey initially grab the crow.

Carol Stalun

The incident is exceptionally unusual for many reasons.

• According to the Cornell Lab of Ornithology's Birds of the World, almost every published account says that 99 percent of the diet of Ospreys consists of live fish, with a wide variety of fish species taken. Fish captured generally measure 25–35 centimeters (10-14 inches) and weigh 150–300 grams (5-10 ounces), although fish up to 2,000 grams (4.4 pounds) have been reported. According to The Sibley Guide to Birds (2nd edition), a Fish Crow weighs 280 grams (about 10 ounces), so it is in the normal weight range of fish Ospreys normally catch. A Fish Crow measures 38 centimeters (15 inches), so its body is only slightly above the size range of normal Osprey prey.

• Ospreys are one of the most widely-distributed birds in the world. They are found on all continents except Antarctica. Unlike most bird species who conceal their nests, Ospreys build huge nests, usually in open areas. The nests are easy to monitor and study. Some nests are equipped with webcams so that researchers can see exactly what prey is being captured. There is believed to be no documented evidence of an Osprey bringing bird prey to its nest.

• According to Birds of the World, there are anecdotal observations of Ospreys catching non-fish prey, including birds, snakes, voles, squirrels, muskrats, salamanders, mollusks, and even a small alligator. There is a documented report of an Osprey attacking a lure pigeon used by hawk banders at Cape May, New Jersey. A lure bird is placed in a small harness, and its flapping induces hawks or falcons to fly into a nearby net. The lures are captive birds who are not wild.

• Birds of the World also mentions reports of Ospreys trimming their nests with the skeletal remains of birds, but this might not represent prey taken. For instance, remains of birds found in nests in Arabia were up to the size of a Socotra Cormorant (80 centimeters, or 31 inches) and Slender-billed Gull (37-42 centimeters, or 14.5-16.5 inches), but it is unclear how or if these species were caught by an Osprey. An Osprey expert with whom I communicated suggested that the dead crow might have been put into the nest for decoration rather than to be eaten. We do not know what happened to the crow after it was deposited in the nest. But Ospreys are not known to decorate their nests with either birds or feathers. Ospreys sometimes interweave plastic bags or other refuse into their nest. This might to be done more for structural rather than aesthetic reasons.

• An Osprey usually will not bother other birds unless it feels threatened. I spent many hours shooting footage of an Osprey nest at the Belle Haven Marina in Alexandria for my videos Osprey Love Nest and Osprey Love Nest 2: Feeding and Fledging. The Belle Haven nest was on a piling in the river, near a boat ramp. The Ospreys at that nest were not bothered when ducks, geese, and grebes swam directly under the nest, and they never showed any interest in attacking these birds. The Ospreys also paid no notice to House Sparrows who built a nest among the sticks of the Osprey nest. Only large birds flying above the nest caused the Ospreys to become alarmed.

• The crow was not scavenged, because it was clearly alive in some of Stalun's photos. Had it been injured and flapping around in the water, it is unlikely that the Osprey would go after it. Ospreys often see uninjured birds swimming and flapping in the water, and they normally leave them alone. I don't know if a certain type of thrashing in the water might trigger a different response than an uninjured bird swimming. I am unaware of any reports of this happening.

• Crows do not often attack Ospreys. The corvid expert Dr. John Marzluff, from the University of Washington, sent me an article that he co-authored about the mobbing of Ospreys by American Crows. The article said that American Crows aggressively mob a variety of natural predators and learn to recognize unique threats. Because mobbing is a costly and risky behavior, Marzluff and the other authors hypothesized that crows would selectively ignore benign members of other species that look similar to predators, perhaps even learning to do so. Through a series of natural observations and experiments, they found that American Crows were more likely to mob Red-tailed Hawks and Bald Eagles than Ospreys. Mobbing intensity was higher toward a taxidermic mount of a Red-tailed Hawk than toward a mount of an Osprey, indicating that mobbing increases with the risk posed by the predator. However, the authors also found that Ospreys were more likely to be mobbed in locations where they rarely occur, suggesting that crow populations that frequently encounter Ospreys habituate to this benign raptor. For the incident that Stalun witnessed, the Osprey was in a location where it regularly occurs, and it is possible that the mobbing behavior by the Fish Crows began only after the Osprey had seized its victim.

• An Osprey expert with whom I communicated suggested that the crow might have been trying to get at a fish the Osprey had caught. This is improbable, because had the Osprey been flying with the fish, the crow would not have been able to carry it, even had the Osprey let go of it. Also, it is unlikely that an Osprey with a fish (its normal food) would drop it and grab a crow (not its normal food).

• The most likely explanation might be that a Fish Crow was harassing the Osprey and got a bit too close. Smaller birds tend to attack a larger bird in groups rather than as individuals because there is safety in numbers, and the larger bird will have more difficulty grabbing any one of them. Osprey's have very strong legs and feet, and if the one Stalun saw managed to grab the crow's back, the crow would not have had much of a chance to escape. When the Osprey took the crow to the piling, it pecked at it, perhaps to kill it and make it easier to carry. It is not known whether the Osprey ever ate the crow.

Photographs of the Osprey with the crow can be seen at Stalun's website . The 60 photographs show the encounter in chronological order, starting with the Osprey holding the crow on the first piling and ending with the Osprey dropping the crow into the nest. Stalun's photographic documentation of this event is an example of how citizen science can produce an important contribution to ornithological research. 

William Young is a writer from Arlington, Virginia. His book The Fascination of Birds: From the Albatross to the Yellowthroat was published by Dover in 2014. He has taught numerous classes about birds for the Audubon Society of Northern Virginia. The nature videos he has created for his YouTube channel have had more than 650,000 views. Along with Ashley Bradford, he is the co-creator of the MPNature.com website, which contains a wealth of information about the natural history of Monticello Park in Alexandria, VA.