Thursday, September 22, 2016

NYC Estuary A Welcome Stopover for Diverse Bird Life

Over the last few years, we have cultivated a relationship with the NYC Audubon, resulting in biweekly Birding Tours of the park during migration. We've been delighted as our Audubon Guide Gabriel Willowteaches us about the avian life of NYC, and helps us spot some of these magnificent creatures up close. Now Gabriel shares his experiences in the park.

Have you noticed a hint of fall in the air recently? The past few nights & mornings have been cool & brisk, although the official Autumnal Equinox isn't for a few days yet (it will fall on today, September 22), fall migration is well underway.

As I have discussed in past Bryant Park Blog posts, the park, like other green spaces in NYC, becomes a hotbed of bird activity during the spring & fall migration seasons. But what is it about the park's location, and our city's location, that makes this area so rich in bird life? Despite the frequent jokes I hear about how the only birds we must see on our urban bird walks are pigeons, NYC has an exceptionally high diversity of birds. The number of species seen in Bryant Park to date stands at 121 species!

New York City is unusual in that it is an archipelago of islands (plus one peninsula, The Bronx). We are located at the confluence of the Hudson River as it empties into NY Harbor, and the East River, which is really a tidal strait connecting NY Harbor to Long Island Sound. There are also a number of smaller rivers, creeks and streams (such as the Bronx River) emptying into these larger waterways.

This landscape, where fresh water & salt water mix & meet the land, is called an estuary. Acre-for-acre, estuaries are the second-richest ecosystem on the planet, following tropical rainforests. Estuaries range from mud flats to salt marshes to mangrove swamps. They are where many species of fish spawn, due to more protected, shallower waters with lots of nutrients and fewer large predators. However there are still many predators: the abundant little fish attract many larger fish, which in turn attract many bird species, such as gulls, herons, egrets, osprey, and more.

Now, what does all this have to do with Bryant Park, you might well ask? Well, it's easy to forget in the hustle and bustle of midtown that in NYC we're never far from the coast, and always part of a larger estuary ecosystem. We had a reminder of this fact on a recent Bryant Park walk, when a Herring Gull (the classic "seagull", although that's a bit of a misnomer, as it is generally found along the coast, and not out to sea) went winging by down 42nd Street. Gulls can turn up anywhere in the city!

Also, many landbird species, such as warblers, sparrows, and swallows follow the coastline during migration. This could be because of more favorable steady winds, or because it forms a highway-like landmark for them to follow (southward, in this case).

Birders seek avian sightings. 

As it happens, NYC is located at a major turn in the road: the coastline bends from a primarily east-west orientation (from the coastal Maritime Provinces of Canada down through New England to Long Island) to a primarily north-south orientation (from NYC all the way to the tip of Florida). This makes our region a natural stopping point as birds shift direction: they are funneled into NYC as they make their way south-west down the New England coast and along Long Island.

Historically, this would have been an exceptionally rich area with a diverse range of habitats: coastal dunes, salt marshes, and mud flats; sandy oak-pine forests interspersed with grassy prairies on Long Island and along the immediate coasts; and hardwood oak/chestnut/maple forests in the upland areas atop the Palisades or in the hillier reaches of Manhattan. Things have changed over the years: the American Chestnut is nearly extinct, largely wiped out a century ago by chestnut blight, and most of our area's forests have been cut and our marshes filled or drained. It is a testament to the richness of this estuary ecosystem that we still have over 350 species of birds recorded in Brooklyn alone, and over 200 species of fish in the Hudson River. This in spite of centuries of radical habitat alteration, pollution, and the construction of a canyon-like habitat of glassy skyscrapers (which pose a major obstacle and threat to migrating birds), every fall NYC still fills with birds from points north, heading to warmer regions to the south.

With this bigger picture in mind, I hope you will join me in Bryant Park on a Monday morning at 8am or Thursday evening at 5pm to see what bird species have shown up in this little urban oasis.

Fall Birding Tours
September 12 - October 17
Mondays, 8am-9am
Thursdays, 5pm-6pm

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