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Meet the Birds of the NY-NJ Harbor Estuary!

Updated: 5 days ago

When you set sail aboard Tantara, between the Brooklyn Bridge, the Statue of Liberty, and the glittering skyline of Lower Manhattan, it’s not hard to believe you’re sailing in the world’s most urban harbor. But would you believe you’re also sailing in an estuary whose biological productivity and natural diversity is rivaled only by coral reefs and rainforests

It’s true! 

An estuary is an ecosystem where a freshwater river or stream meets the ocean. In the case of the NY-NJ Harbor Estuary (also called the Hudson-Raritan Estuary), it’s where the Hudson, Hackensack, Passaic, Rahway, and Raritan rivers meet the Atlantic Ocean. It includes tidal straits such as the East River and Arthur Kill, as well as diverse bays such as Jamaica Bay Wildlife Refuge, Raritan Bay, and the Upper New York Bay—aka New York Harbor. 

The water in an estuary is brackish—which means it’s salty, but not as salty as ocean water. That’s because water continuously circulates into and out of an estuary, with tides creating the largest flow of saltwater, and river mouths creating the largest flow of freshwater.

This unique combination of salty and fresh water creates a variety of nutrient-rich habitats, such as tidal wetlands, natural shorelines, shallows, submerged aquatic plant beds, river bottoms, and tributary streams. And the incredible diversity of life supported by these habitats provides an abundant food source for both migratory and resident birds.

In fact more than 300 species of birds visit the NY-NJ Harbor Estuary annually. While you're not likely to see many on our sail, we thought you might like to meet a few of them here in our blog, with a little help from NYC Bird Alliance, the only organization in New York City dedicated to protecting wild birds.

The Harbor Herons

NYC Bird Alliance nesting surveyors have observed 10 species of egrets, herons, and night-herons nesting on 16 different islands around the harbor. You can get to know all of the harbor herons here, but we’ll share a few of our favorites.

Black-crowned Night-Heron

Black-crowned Night-Herons are gray, black, and white birds recognizable by their eponymous black crown and squat, thick proportions. They migrate south in the winter, but stay in the New York City area year-round during milder years. When it’s not breeding season, they often roost together in large groups in trees hanging low over water. They’re most active at dusk and in the early morning, but can also be seen during the day—especially during breeding season, because breeding is hungry work.

Green Heron

Green Herons are small, stocky birds who tend to keep to themselves. Adults have a glossy, green cap often raised into a sharp crest, charcoal wings tinted with green or blue, and a chestnut neck with a white line down the front. They hold their necks tight to their bodies, which gives them a hunched appearance. With dagger-like bills and sharp yellow eyes, Green Herons cut a striking image perched motionless at the water’s edge, waiting for prey to swim within striking distance. But Green Herons do more than just wait. They’re one of the few birds that use bait (and infinite patience) to lure their prey close enough to the surface to catch them, by tossing a twig, leaf, feather, or even a live insect into the water.

Glossy Ibis

The Glossy Ibis wouldn’t look out of place on the red carpet of any bird awards ceremony. Though their feathers may look dark from a distance, closer inspection reveals a deep maroon body, and wings that sparkle with hints of iridescent bronze, green and violet. Unlike the solitary Green Herons, Glossy Ibises flock together, and typically feed by lowering their long, curved bill into water, mud, or soil, to feel for prey. 

Beach Nesting Birds

Every year, from April through August, Common and Least Terns, Black Skimmers, American Oystercatchers, and Piping Plovers nest on the bare sands of New York City beaches and inlets, laying their eggs in shallow scrapes in the sand, above the high tide line in open, sandy areas with little vegetation. While you can get to know all of the beach nesting birds here, we’re partial to these two.

American Oystercatcher

American Oystercatchers are as unmistakable as they are adorable. They're large, thick-set birds that have a coal black head and neck, a dark brown back, a white belly, and white patches on their wings and tail. They have a long, straight bill the color of a traffic cone, and adults have yellow eyes encircled by that same traffic-cone orange. If you had to draw a goofy cartoon sketch of a mollusk-eating shorebird, the American Oystercatcher is what you'd draw.

Once known as the "sea pie" (we’re not sure we want to know why), the American Oystercatcher was renamed in 1731 when naturalist Mark Catesby observed one eating oysters. In fact the oystercatcher is one of the few bird species that specializes in feeding on saltwater mollusks.

Piping Plover

Speaking of adorable birds, Piping Plovers. There’s a reason the Piping Plover is the poster-bird for threatened beach-nesting birds. They’re rotund and stocky, with round heads, large, dark eyes, and short, stubby bills. Adults have a black band across the forehead from eye to eye, and a black neck band. They feed on invertebrates they find on beaches and mudflats, and in NYC they nest exclusively on the beaches of the Rockaway Peninsula, in Queens.

Migratory Shorebirds

Each spring and again in late summer, migrating shorebirds make a pit stop in New York City to refuel in our marshes and on our beaches and mudflats. You can read all about them here, along with all NYC Bird Alliance is doing to research their food sources and movements so they can better understand their ecological needs and support their conservation. But here we’re going to focus on the Red Knot, because they're amazing.

Red Knot

Red Knots are large, colorful sandpipers that can be found on every continent except Antarctica. Their migration every spring and fall between their wintering grounds in Tierra del Fuego and their nesting territory above the Arctic Circle is the longest of any animal—up to 9,300 miles, including nonstop flights of 1,500 miles or more!

The Rufa Red Knot, the subspecies that passes through our area, times its spring migration with the spawning of the Atlantic Horseshoe Crab, as it depends on their energy-rich eggs to fuel its long flights. Red Knots from eastern North America have declined sharply in recent decades owing in part to unsustainable harvest of horseshoe crab eggs, and they have become a flagship species for shorebird conservation in the twenty-first century.

Red Knots also eat hard-shelled mollusks, probing into sand or mud with their stout black bills. They use specialized sensory organs in their bill tips to alert them to differences in water pressure, which tells them a meal is nearby. They swallow the shells whole, and crush them up in their gizzard—the muscular part of their stomach. 

The oldest recorded Red Knot was almost 19-years-old. 


We hope you’ve enjoyed learning a little about the estuary where we sail, and the resident and migratory birds who depend on its natural diversity. If you want to help NYC Bird Alliance keep New York a great place to live for birds and people alike, you can make a donation here.


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