Protecting the Hudson Valley’s Great Swamp

Spanning some 6,000 acres in Dutchess and Putnam counties, the Great Swamp is an ecological treasure teeming with wildlife

When you take Metro-North’s Harlem Line train from Dover to Southeast, you’re traveling through it. When you drive along Route 22 in the Pawling area, you’re catching views of it. And as you ride the lift at Thunder Ridge Ski Area in Patterson, it’s all around you.

Running on a north-south axis some 20 miles through Dutchess and Putnam counties, the Great Swamp seems to be everywhere. And yet, the only mention of it you see from the road is on the reverse side of signs when entering and leaving the town of Patterson.

Swamps in general don’t get a lot of good PR — most people think of them as mosquito-infested wastelands. Yet the Great Swamp — which flows two ways, north to Long Island Sound and south to the east branch of the Croton River — enhances the quality of life for everyone who lives in its 63,000-acre watershed and beyond. For one thing, the slowly flowing swamp filters water by sequestering pollutants — and that’s good news not just for the 40,000 residents of the watershed itself, but also for the one million-plus denizens of Westchester and New York City who use the Croton water supply system. During a drought, the swamp recharges the surrounding aquifer with its moisture; during heavy rainfall, it becomes a sponge that prevents flooding. It provides habitat for the great diversity of animals who live and migrate there, and it gives us humans a place to unwind — in a setting that’s as close to wilderness as you’re going to get — just a short drive from home.

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Despite these perks, though, people still tend to take the swamp for granted. “Many lifelong local residents don’t really know about it or realize it’s here,” says scientist and historian Judy Kelley-Moberg, a board member of Friends of the Great Swamp (FrOGS), a group formed in 1990 to preserve and raise awareness of the swamp. “It’s a hard sell, because they can’t really see what it does. Up to the time that FrOGS was founded, wetlands were just thought of as places to dump, drain, or ignore.” In fact, a proposal to build a garbage dump in the town of Patterson “started the ball rolling in terms of protection of the swamp” Kelley-Moberg continues. “Then Governor [George] Pataki took a canoe trip through it, and was so impressed he vowed to pledge money to protect it.”

Since its founding, FrOGS has protected more than 1,000 acres through federal grants; most recently, the group partnered with the Putnam County and Westchester land trusts to preserve the sensitive Ice Pond Conservation Area’s 115 acres.



Once they’ve gotten a taste of it, many people become lifelong devotees of the swamp. One of its most ardent supporters is FrOGS Chairman Dr. Jim Utter, an environmental scientist and recently retired SUNY Purchase professor who has made the swamp his laboratory for 40 years. You’ll often see his hatchback, with the license plate “GRT SWP,” parked near canoe access points.

Utter regularly leads FrOGS-sponsored paddles through the wetlands’ meandering channels, which culminate at Pine Island — the heart of the swamp and a winter snowshoeing destination. Along the way, he points out things that you might not notice otherwise: a muskrat quietly swimming through the sedges, a hidden colony of nesting herons, a wood duck in flight. He also explains what makes a swamp a swamp: It is a wetland dominated by woody vegetation (as opposed to a marsh, which is grassy).

“The ecological diversity arises primarily from the geology,” explains Utter. “Underneath us is a soft marble ‘basement’ that forms the broad, flat floodplain.” This marble, a metamorphic form of limestone that is the remains of an ancient sea, makes the swamp “sweet.” That is, it conveys a nonacidic, calcium-rich groundwater that gives rise to uncommon ecosystems, not to mention uncommon animal species. (The same marble, once mined here, also supplied the building blocks for many of Patterson’s grander homes.)

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Oddball plants thrive here: Long’s bittercress, a rare plant that is on the verge of extinction; southern dodder, documented in only one other location in New York; and exquisite, sought-after wildflowers like marsh bellflower and blueflag. Freaky insects in residence include the water strider (called the “Jesus bug” because it walks on water) and the hard-to-find olive hairstreak butterfly, which depends upon red cedar for food. In fact, some 60 species of butterflies have been identified here, along with eight species of crayfish and more than 58 types of dragonflies and damselflies. And don’t forget the mammals: bear, bobcat, otter, beaver, mink, fox, and coyote all fill a niche. Noteworthy reptiles include bog turtles, an endangered species that Utter tracks using transmitters. Even freshwater mussels, an indicator of high water quality, can be found here.

And then there are the birds — black- and yellow-billed cuckoos, red-shouldered hawks, hermit thrush, cerulean warblers, American bitterns, and marsh wrens. Every spring and fall, FrOGS members gather in the swamp to track waterfowl migration. Some 5,000 ducks — a mix of wood ducks, mallards, black ducks, and blue-winged teals — have been counted entering the Ice Pond area in a single evening. “It’s like squadrons of airplanes coming in overhead,” says Kelley-Moberg. Lucky birders can get a look at baby wood ducks being coaxed out of their nests to make the dramatic leap to the water below. No wonder the swamp has been designated both a National Historic Landmark and an Audubon Society Important Bird Area.

Lush and mysterious, the swamp has a slightly Gothic feel. “The thick forested floodplain is reminiscent of a southern swamp or bayou in a way that is unusual in the north,” says Utter. Which is perhaps why Disney sent noted photographer Annie Leibovitz there to shoot a “dream portrait” of actress Jennifer Hudson dressed as Tiana, the title character of the film The Princess and the Frog. “It was the only place they could find a swamp that still looks like a swamp, though they added a fake frog and lily pad,” says Kelley-Moberg.

great swamp frog


But that frog didn’t get nearly as much press as a newly discovered — and as yet unnamed — species of leopard frog.

What started out as a dissertation project by Rutgers graduate student Jeremy Feinberg in 2012 turned into a monumental discovery. Feinberg was trying to figure out why the southern leopard frog had disappeared from much of its former range. Then what Feinberg calls a “fortunate accident“ occurred. While out listening to what he thought was the southern leopard frog’s call, he suddenly realized that he was onto something new. “I thought, ‘This thing is different for sure.’ ” Realizing that the call matched neither that of a southern nor northern leopard frog, Feinberg and his colleagues arranged for a DNA test that confirmed the new, separate species.

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After he got confirmation that the frog was different, Feinberg changed the whole focus of his dissertation. “This news was just so urgent and of the moment,” he says now.

“Even before it was suspected to be a new species, it was very likely the rarest amphibian in New York,” says Dr. Matt Schlesinger, chief zoologist for the New York Natural Heritage Program and a professor at SUNY College of Environmental Science and Forestry. “Now it appears that the southern leopard frog never occurred in the Hudson Valley. This particular guy is what we used to call the southern leopard frog. It is unusual to find that, in a heavily developed area and among such a well-known group as frogs, there is something unique and hidden. It’s called a cryptic species, because it looks, acts, and sounds like other species superficially, but when you dig in, you find that it’s not.”

great swamp turtles


Once you open your eyes to the Great Swamp’s presence, it seems to be everywhere. Still, the challenge is how to get onto it. Most people opt to use a canoe or kayak — the swamp has 14 miles of navigable water, which is at its highest in spring, with the level dropping throughout the summer and disappearing in parts through winter (when snowshoeing is possible). The most popular access points are the Patterson Recreation Area, where you can drive over the Metro-North tracks down a dirt road and put in; and at Green Chimneys school at the Patterson/Southeast town line.

Boaters also can paddle around Ice Pond Conservation Area, a crystal-clear glacial lake that was once the site of an ice harvesting operation that supplied New York City. “There are remains of an old brick factory, so you get to see what Putnam looked like a century ago,” says Judith Terlizzi, president of the Putnam County Land Trust, which owns the preserve. Anglers love the place for its bass and perch, but getting a boat down there requires a bit of work. Instead, you may want to check out the trails that surround the pond, close by the wetlands where the mystery leopard frog was first documented. “Hikers can walk all along Ice Pond down to Route 311 from 164, which was supposed to be part of the rail trail,” says Kelley-Moberg. “If a span of rail trail is ever completed, it would open it up even more.”

Ice Pond has also become a mecca for bouldering, a trendy niche sport that is akin to rock climbing without the gear. “They climb on the sheer face of the rock off the western side of the pond,” says Kelley-Moberg. Another popular hiking spot is the stretch of the Appalachian Trail on Route 22 in Pawling, which also happens to have a Metro-North stop nearby. A lovely boardwalk meanders through marshland there.

great swamp kayak


Even though there is plenty of wildlife in the swamp, it’s not always easy to see. That’s why it’s so much fun to look at David Henningsen’s photos.

A transplant from New York City, Henningsen came to Patterson some 20 years ago. “When I first moved here, people considered the swamp a burden,” he recalls. “But I was looking for a getaway, and economic times said I wasn’t going to the Caymans or Tahiti, so I got a kayak and went in.” By 2008, Henningsen began bringing along light camera equipment on his near-daily visits. “You really do get away. You feel like you could be going back to the Jurassic period, minus the dinosaurs.”

In time, he built a collection of swamp scene photos — dragonflies in closeup, blue herons that resemble pterodactyls, plants in exquisite detail. One of his favorites is an image of a lone frog with its bulbous eyes peeking intently out of the water, the rest of its body submerged. “That was just one of about 15 little frog heads staring at me that day,” he says. “If you just sit quietly and don’t move, the animals come out — and some even come to check you out.”

Lush and mysterious, the swamp has a slightly Gothic feel that is “reminiscent of a southern swamp or bayou,” says Utter

The photographer often waits for hours at a time to get the right shot; on one occasion, he was jostled to attention when something that felt like a fist hit him from below, followed by a blow to the side of the boat. “Then I saw the tail,” he recalls. “It looked like it belonged to an alligator.” It turns out that he had unknowingly parked his kayak in a snapping turtle’s territory. “They are formidable animals — all neck.”

Most of us would never dream of venturing into the swamp at night, but Henningsen makes it a habit. “That’s when the mink and beavers come out,” he says. And, no, he doesn’t worry about getting lost: “If you go with the flow, you’re heading to Green Chimneys. If you go against the flow, you’re heading toward Route 22 in Patterson.” Even if he encountered an emergency, he would be able to call for help. “The swamp has better cellphone reception than my house.”


The new species of leopard frog doesn’t yet have a name, but here’s how to recognize it:

Size: Smaller than a typical pond frog, usually two to three inches long from snout to the beginning of the legs
Color and markings: Green or brownish skin, with contrasting rounded spots that can be green, tan, or dusky brown. There have been unconfirmed reports that the frog can change color.
Physical features: Two dorsal lateral folds, which are parallel lines that run down their backs
Call: Sounds like “brah!”; has been described as a snore, wheeze, chucking, or even retching

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