Osprey Nation Holds On

When I went on my latest rounds monitoring local osprey nests, I was relieved to find the ospreys still here. The mother ospreys were guarding their nests. The fathers were out looking for the fish that make up their entire diet. The heads of some of the recently hatched osprey chicks were starting to become visible above the sides of the nest.

I hadn’t been sure what I would find.

I was glad that the predicted severe storms of the night before hadn’t materialized in our area. A powerful storm in September 2021 had destroyed the nest designated as ​“Hamden #13” by the Connecticut Audubon Society Osprey Nation group. But by that time last year, the ospreys had already left their Hamden home, destined for their winter domiciles in South America. 

It takes a lot of wind power to knock over an established osprey nest, which is built from sticks and lined with softer material. Mature ospreys who have been breeding for several years return to the same structure annually and continue to build it wider and deeper. The average thick-walled osprey home might be five feet wide, six feet deep, and weigh 300 pounds. 

The nests might be placed on one of the osprey platforms that have been built in wetlands by municipalities, organizations, or even individuals. The birds also choose other human-made structures such as pilings, utility poles, or cell phone towers as bases for their nests.

Here in early July, the nests are still occupied, and the recently hatched chicks are being fed by their parents. Last Sunday, everyone was safe. 

I’ve lived on a boat on the Quinnipiac River for several years and have become fascinated by these ​“fisher hawks” and their yearly cycle of raising families in their large stick nests. To find food, the birds use their almost superpower vision to search for fish from as high as 100 feet in the air. Once the prey is located, the bird dives at up to 50 miles per hour and plunges into the water, feet first, to grab the fish in its strong talons.

The osprey is an ancient bird; fossils from the Pandionidae family date back 14 million years. They live on every continent except Antarctica.

In 2021, I took my interest in these birds a step further and became an official Osprey Steward with the Osprey Nation organization, which is part of the Connecticut Audubon Society. I monitor the health of nine nests in New Haven, Hamden, and North Haven.

Along with their fishing prowess and architectural skills, another of the osprey’s extraordinary feats is its yearly fall and spring migrations between its North American home to wintering grounds in Central and South America. Every autumn, over a two-week period, each osprey makes a solo voyage of 2,500 miles or more along the Atlantic coast, through Caribbean islands, and across Venezuela to their final destinations in the Amazon Basin. In the early spring, the bird reverses its course and flies back to the nest it occupied the year before, which is usually close to where it was raised.

Young osprey who have never made this trek before instinctively know where to go without any guidance. In writing this article, I hoped to be able to connect to scientists who could help explain this fascinating migration, which mirrors that of many songbirds and other species.

Although the ospreys now have a conservation status of ​“least concern,” they were highly endangered in Connecticut in the early 1970s due to the polluted waterways that couldn’t sustain healthy fish populations and reliance on DDT to control mosquitoes. The osprey absorbed the DDT in their diets, and the pesticide so weakened the birds’ eggshells they cracked during incubation. 

By 1972, when DDT was banned in Connecticut, there were only around 10 pairs of nesting ospreys in the state. The passage of the Connecticut Clean Water Act of 1967 and the Water Pollution Control Act of 1972 improved the health of the rivers and once again allowed fish populations to thrive.

Milan Bull, senior director of science and conservation for the Connecticut Audubon Society, explains that ospreys are good indicators of the health of our region’s waterways. The osprey’s preferred meal is the menhaden, or bunker, which feed on phytoplankton. These species thrive in clean water but are seriously affected by pollution.

As the health of the osprey population gradually started to improve, humans began to help rather than harm them, building platforms and trying to protect their habitats. Connecticut’s Department of Energy and Environmental Protection (DEEP) began monitoring the population. In 2014, state biologist Julie Victoria called on the Connecticut Audubon Society to help with the osprey project. 

Milan Bull took the program in a new direction by giving it the name ​“Osprey Nation” and turning it into a ​“citizen science” effort.

“People love ospreys,” Bull explained. ​“They are big, beautiful raptors who nest in visible places along waterways, so we have no trouble getting volunteers to monitor osprey nests. We are accumulating a lot of data, and our main goal is to see how many active nests we have every year and how many birds fledge.”

The program started with 100 volunteers in 2014. In 2015, 146 volunteers monitored 250 active nests that yielded 356 fledglings. By 2021, 342 volunteers monitored 558 active nests and counted 858 fledglings. The complete data can be seen here.

Osprey Nation Project Coordinator Breanne Ellis works directly with the osprey stewards and also manages the data collection. Bre says, ​“One of my favorite parts is connecting with all the stewards. People want to share their experiences and photos with me.” 

Even armchair osprey enthusiasts can monitor the yearly cycle of the osprey chicks through webcams set up by the Menunkatuck Audubon Society [1] at Hamonasset Beach State Park and West River Memorial Park in New Haven.

At the time of this writing, each nest has two chicks, although the mortality rate for first-year osprey is 50 percent or more. The eggs and chicks can fall prey to marauding eagles, large owls, crows, and even raccoons and foxes who raid nests that aren’t in a high enough location. As you can see by looking at the webcam images, the feather pattern of the young birds blends in with the sticks and camouflages them from would-be predators.

A disclaimer at the webcam sites states:

This is a wild Osprey nest, and anything can happen. While we hope that healthy Osprey chicks will end up fledging from the nest this summer, things like sibling rivalry, predators, and natural disasters can affect this Osprey family and may be difficult to watch. As hard as it may be to see anything happen to our Osprey, we will let nature take its course and not intervene.

Some of the more squeamish webcam viewers may also wish to turn away if daddy brings home a live fish, fresh from the water and still flapping. While the ospreys will enjoy the meal, it isn’t such a good day for the fish.

The young ospreys currently in the nests were born in May or June after an incubation period of 38 to 42 days. The young birds stay in the nest from 50 to 55 days, although by the end of the first month, they can be seen starting to flap their wings until eventually they are able to rise above the nest. 

After they fledge, the youth continue to return to the nest for another couple of weeks and are fed by the parents. They slowly become more independent and learn to fish for themselves with no instruction from their mother or father. In September, the mother and young birds leave the nest first, and the father leaves last. As mentioned earlier, each osprey makes a solo flight, unlike species like geese who fly in groups.

To understand how recently hatched birds make this flight, researchers attached a radio transmitter to a storied first-year osprey named Penelope in 2008. The scientists followed her as she left her nesting area in Martha’s Vineyard and traveled 2,700 miles in 18 days to French Guinea. She stayed there for 18 months until she reached breeding age.

The four hungry and uncoordinated young ospreys seen here on the Menunkatuck Audubon Society webcams in early July will make a similar trek in eight to ten weeks. Like Penelope, these young ospreys will stay in their South American homes until it is time for them to start their own families. They will then make a springtime voyage north, again guided by a mysterious instinct, to the same location where they were hatched two years previously.

Ospreys in other parts of the world make similar treks from other areas. Ospreys in northern Europe fly to Africa, and only some birds with plentiful fish throughout the year (in Florida or Australia, for instance) might stay closer to their breeding grounds.

The male ospreys always return to the nests first. Older birds will repair and further build out their nests from the year before, and young birds will build their first nests. After the females return, the males begin an elaborate courtship ritual called ​“sky-dancing,” in which they soar hundreds of feet in the air and then swoop down, sometimes carrying a stick or a fish. 

The young males will also try to attract a mate by bringing gifts of fish. Not surprisingly, research has shown that a male who provides lots of fish is more likely to successfully attract the female of his choice. Once a pair is established, they will remain together for life, although they don’t winter together. The breeding takes place over several days, with the female laying eggs one or two days apart, usually two to four in a nest. The eggs will hatch in the same order. The average osprey lives for eight to 10 years, although some have lived more than 30 years.

Although the osprey population was rescued from almost-extinction one time, it is not known how climate change and other environmental threats will affect these birds. With the recent Supreme Court ruling that will almost certainly increase carbon emissions, temperatures throughout the world will also increase.

What I termed as the osprey’s ​“mysterious instinct” to migrate is likely to also involve such ordinary factors as finding expected food sources throughout the migration area and in South America, and those food sources could disappear or shift locations. Climate change also increases the numbers of hurricanes and other destructive storms that claim the lives of many ospreys on the migratory path. 

And while our country currently has laws on the books that protect the quality of the water, the countries in the Amazon Basin where the ospreys spend their winter months have seen massive deforestation.

The Connecticut Audubon Society’s Milan Bull described the osprey as the ​“canary in the coal mine.” Negative changes in their habitat will affect the water, plankton, menhaden, and ultimately the birds. He says he hopes we never see an environmental disaster like an oil spill from the many tankers that travel on the Long Island Sound. He says that the current population explosion will probably level off because the growing numbers of birds will be unable to find good nesting spots. 

An ongoing threat to osprey is litter because they like to use all sorts of soft objects to line their nests, some of which can be harmful. Milan Bull thinks that osprey might have a preference for blue things. This can be amusing, such as when an osprey recently brought a blue teddy-bear into its nest and kept rearranging it. But if the object is a plastic bag or, worst of all, fishing-line, the outcome can be deadly. An all-too-frequent occurrence is when ospreys, particularly young birds, become entangled in the line and are unable to get free.

The Connecticut DEEP is working with local groups and marinas to install receptacles for the safe disposal of fishing-line, hooks, lures, and other material that might harm osprey and other birds that live along the water. The list shows that while Hamden currently has one such receptacle near Sleeping Giant, New Haven has none.

In my conversation with Osprey Nation’s Milan Bull and Bre Ellis, I returned to the topic of osprey migration and asked what is known about the birds’ ability to instinctively make such a long trip to South America and then precisely return to the location where it had been born. Bull says that the birds do follow the food resources, and fish like the menhaden also migrate to warmer climates and disappear from our area. 

Ultimately, though, what guides the birds is a mystery. As Bull says, ​“This is why birds are so incredibly fascinating. Not only do they provide activity and songs to our lives, but there is so much we don’t know about them yet. They are fascinating creatures.”

Osprey Nation starts enrolling osprey stewards in March of every year, but some existing nests still need monitors this summer. You can find out more information here.

My thanks to the very talented Monica Nichols for use of her beautiful osprey photography. Monica’s website is www.thewalkingbirdnerd.com.

[1] The Menunkatuck Audubon Society is the local chapter of the National Audubon Society, which was founded in 1905. The Connecticut Audubon Society is a separate organization formed in 1898, at about the same time as similar organizations in other New England states. These groups had the goal of protecting shore birds whose populations were being decimated by the fashion at that time for bird feathers in women’s hats.