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In This Place

Trek to the Tidal Flats off Monomoy a "Must" for Birders

Eric Vondy / flickr
Marbled Godwit. Four Marbled Godwits were spotted feeding on tidal flats at South Beach this past week, in an unusual sighting.

These fragile outposts, the Cape and Islands are the most geologically dynamic area that one can imagine, with the exception of an erupting volcano. The constant and variable pressures of eroding sand and clay shorelines, sculpted by wave action, currents, tides and the prevailing wind, is a landscape in flux. Mirroring life, the only constant is change.

The waves, winds and flow of currents has created an area where Nantucket Sound meets the Atlantic Ocean, where change can be seen from storm to storm, indeed almost from one high tide to the next. There are mile after mile of shallow tidal flats bathed in the bathtub temperature water of Nantucket Sound that collides with the cold, oxygen rich water of the North Atlantic. This makes it one of the foggiest places on the planet during the summer months.

The overall effect of this mixing of the waters, other than lots of fog, is an incredible abundance of invertebrate life - a stew of organic life. The volume of life - the numbers of clams, marine worms, euphosids, amphipods, crustaceans and a veritable soup of “animals without backbones” - provides an abundance of food for migrating shorebirds.

Of all the places on the Cape and Islands, Coast Guard Beach, the barrier beach section of Nauset Marsh in Eastham and the “elbow” of Cape Cod, in Chatham, which includes a myriad of beaches and tidal flats including amazing South Beach and the Monomoy Islands, are far-and-away the best place to see remarkable numbers and variety of birds. These areas play host to many tens of thousands of shorebirds in migration, including many species that are such strong flyers that they rarely turn up anywhere they don’t want to be.

What this means for birders is that if you want to see some of the rarer species of shorebirds, gulls, terns or seabirds you will want to visit these areas. It is worth the effort, and every trip is memorable, including the ones when the fog rolls in and you can’t see your hand in front of your face.

Birders from all over the country and the world make the trip to visit Eastham and Chatham at this time of year for both the numbers and variety of shorebird species that can be seen. It is one of the best places; maybe the best place on the planet, to see the rare Hudsonian Godwit as it visits during its annual migration that takes it to the ends of the planet. This past week there were dozens of these godwits, as well as four Marbled Godwits, feeding on tidal flats at South Beach.

Hudsonian Godwits are relatively large, Arctic nesting shorebirds that visit here, feeding heavily, doubling their body weight in 2 or 3 weeks, before launching on a spectacular nonstop flight to northern South America. From there, they continue southward all the way to the bottom of that continent, spending the Austral summer on the flats around the Straits of Magellan in Patagonia in southern Argentina and Chile.

In fact all the Godwit species in the world, which are the Black-tailed Godwit, Bar-tailed Godwit, including both subspecies. Hudsonian Godwit and Marbled Godwit have all been seen in Chatham in the past as well. This malleable area is perhaps the best place in the world to see godwits.

For the next several weeks, the shorebird spectacle that is visible at these places is to my mind one of the wonders of the world. It is an awesome and humbling sight to see thousands of shorebirds, going on about their lives that are only stopping here briefly in their annual cycle of winging around a large part of the planet. That the birds know these food-rich areas are there and plan their annual migration to take advantage of them is a gift to us all.