If God wanted birding to be easy, he wouldn’t have created shorebirds. But here they come again, sneaking down our coast, defying identification. It’s enough to make a birder switch to butterflies.
Shorebirds are a diverse group, and they have comical names, such as dowitchers, sanderlings, knots, turnstones, curlews and phalaropes. Not all birds found at the shore are shorebirds. Not all shorebirds are found at the shore. The American woodcock and the Wilson’s snipe are classified as shorebirds, but you’d never find one on a mudflat. Red-necked and red phalaropes nest in prairie potholes but winter out in the ocean.
Thirty-eight species of shorebirds venture into Maine. Only eight breed here. One, the piping plover, is federally endangered, mostly because it likes to nest on sandy beaches, where it runs afoul of predators, dogs, people, Frisbees and dune buggies. One shorebird is state threatened. The upland sandpiper likes large plains of sparse vegetation, and most of those have been turned into subdivisions and shopping malls. Fortunately, they thrive on large blueberry barrens.
I’ve reached the age where I no longer study history — I merely remember it. When I first started exploring Maine’s mudflats, the number of shorebirds was many times higher than it is today. Up to half a million semipalmated sandpipers flowed through Maine each year. Total numbers have fallen dramatically, perhaps because of climate change, perhaps because of habitat loss.
The shorebirds that pass through Maine pursue a risky strategy. Food is plentiful during the brief arctic spring. Shorebirds flock to the tundra to take advantage of this bounty and raise their young. In autumn, they return south, stopping at key mudflats along the way. Many of these important areas are in Maine. Shorebirds use these spots to refuel, feeding voraciously before continuing south.
Shorebird identification is a challenge because many of the birds look similar. Worse, they’re usually distant, foraging way out there in the mud. It’s easy to tell the size difference between a greater yellowlegs and a lesser yellowlegs when they stand side by side. But that lone individual on the other side of the marsh could be either one. Only an experienced birder knows to look at the bill and compare the bird to itself. The bill of a lesser yellowlegs is about the length of the head. The bill of a greater yellowlegs is longer than the head. It’s a clue that has saved me from embarrassment many times.
It’s even tougher to distinguish between short-billed and long-billed dowitchers. Despite the name, there’s not much difference in bill length between the two. They are so similar that when I am guiding other birders, I resort to distraction as a tactic if asked to ID a distant dowitcher. It goes something like this: “I think it’s a short-billed dowitcher because — hey, look, an eagle!”
Fortunately, nature does much of the work for you, sorting out the birds by location. Long-billed dowitchers mostly are out west. They may stray into Maine, but nearly every dowitcher you see here is a short billed. If you see one that looks a little bit different, consult your field guide and good luck to you.
Nature also has sorted the other shorebirds for you by size, habits and habitats. Thirty-eight species may seem like a daunting number of confusing identifications. It discourages many birders. But only about half are actually on the mudflats. Upland sandpipers are in the blueberry barrens. Pectoral and Baird’s sandpipers like wet edges of farm fields. Purple sandpipers forage only on rocks in winter. Solitary and stilt sandpipers favor small wetlands. Western sandpipers are, well, western.
Next, you can sort them out by size. The smallest are semipalmated, least and white-rumped sandpipers. They dominate the mudflats. Sometimes it’s just a matter of figuring out the difference between these three diminutive species. Plovers are slightly bigger, but piping plovers prefer sandy beaches. The mudflats are thus left to the semipalmated and black-bellied plovers. The latter is twice the size of the former, and it’s slightly larger than the American golden plover, a mid-continent grassland species that sneaks onto Maine mudflats in small numbers. Add an occasional killdeer, and you’re really only sorting out four species of plover.
Most other shorebirds are larger. Sanderlings, dunlins, yellowlegs, ruddy turnstones and red knots stand above the peeps. Godwits, willets, whimbrels and oystercatchers tower over those. Focus on learning the small ones, and the rest sort themselves out pretty easily. Or switch to butterflies.
Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.