Wildlife cameras and conservationists along the Bronx River captured footage of a North American beaver (Castor canadensis) near the Mitsubishi Riverwalk in the Bronx Zoo, marking the first confirmed resident since a previous short-time resident disappeared in 2018.
Biology student and Bronx River Alliance intern R.J. Hawkins found the new beaver on trail cameras set April to May. A fresh tree gnawing and saplings cut down also proved a beaver was living and working in the area.
The fact that beavers have returned at all would seem remarkable, but it’s really not. It’s the planned result of efforts of the environmental movement to limit air and water pollution and preserve the open space habitats fish and wildlife need to survive.
It wasn’t always that way. According to the NYC Department of Environmental Protection, “at the beginning of the 18th Century, roughly 12 water mills were producing paper, pottery, flour, tapestries, and snuff along the Bronx River.”
The construction of the New York Central Railroad in the 1840s turned the valley into an industrial corridor. During the 19th and 20th centuries, the river became a natural sewer into which industrial waste was poured every day.
In the 21st century, environmental groups including the Bronx River Alliance have been working to return the river to a more natural state.
Blighted industrial sites have been transformed into public green spaces, including Concrete Plant Park and Starlight Park, and into functioning salt marshes.
Conservationists have fought to protect the river, and have organized volunteers to plant native trees, remove invasive plants, and build experimental oyster and clam beds to filter the water.
Bronx River Rewilding
The return of the beaver is a small indication that decades of cleanup efforts on the freshwater river are paying-off and the river is rewilding.
This has triggered a resurgence of native biodiversity, and is helping to transform the watershed into viable habitat for species that have been absent for centuries. Bobcat, coyote, mink, alwife, american eels, and snapping turtles have moved in.
With the return of healthy fish populations like herring and sunfish, large predatory birds, including ospreys, great blue herons, and egrets are now common sights along the river. The presence of damselflies and dragonflies indicate improved water quality, as their larval stages require clean, oxygenated freshwater to survive.
In 2023 a pod of dolphins was seen swimming in the river.
It could take decades more however, before beaver are re-established on the Bronx River. Bald eagles took about 13 years (1976 to 1989) from their first reintroduction in New York State to an established population. For moose, the state never actively reintroduced them, but they immigrated back naturally in the 1980s, taking roughly six years to form a documented resident population.
But those species benefited from the largest open spaces in New York State, places in the Adirondacks, Catskills, or Rensselaer Plateau. Fish and wildlife rewilding in an urban ecology is more challenging, but is beginning to prove successful.
Cleaner water in the Chicago River brought back over 70 fish species and numerous migratory birds. Seals, seahorses, and sharks now live in the tidal Thames River.
The Hudson River is our notable example. In 2016, when DEC and its partners removed a six-foot dam at the mouth of the Wynants Kill, a once-polluted tributary of the Hudson River at South Troy, river herring were swimming upstream within days to spawn for the first time in 85 years.
“Beavers have not been seen in the Bronx River since José the Beaver in 2018,” Hawkins writes. “José was first spotted in the river in 2007 and was the first beaver seen in New York City in over 200 years. While José and a second beaver, Justin Beaver, [first seen in 2010] lived together for a number of years on the river they are believed to have passed away, leaving a keystone species missing from the ecosystem.”
The most recent Bronx River beaver sightings suggest they now may return – eventually.
Read more about the Bronx River, Urban Ecology, or Rewilding in New York State.
Photo: The Bronx River in Shoelace Park, in The Bronx.
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