GOOD BIRDING

Shorebird identification is easy, unless it’s not

Posted Aug. 17, 2012, at 2:37 p.m.
When identifying birds like this one, Bob Duchesne lives by a simple rule: Every plover  is a semipalmated plover, unless it’s not. In this case, it is.
Photo courtesy of Bob Duchesne
When identifying birds like this one, Bob Duchesne lives by a simple rule: Every plover is a semipalmated plover, unless it’s not. In this case, it is.

Here’s how you know when you’ve crossed the line from being a casual birdwatcher to being a serious birder: shorebirds. Most people would not suffer the woes of walking in shoreline mud just to glimpse a bunch of drab birds that all look alike. Well, now’s the time to test your mettle. It’s shorebird season.

As you read these words, there are thousands of shorebirds sitting on sandbars along the Maine coast, waiting to be identified.

The term shorebird refers to a group of birds that characteristically have long bills, legs and toes. Most frequent the shoreline to probe in the mud for insects, mollusks and small crustaceans. Sandpipers and plovers are the most numerous, and the smallest of these are often referred to as “peeps.” Stilts, oystercatchers and avocets also fall under the heading of shorebird.

Shorebirds are champion migrants, some traveling to wintering grounds as far as the southern tip of Argentina. That puts them at great risk, and humans aren’t helping much. In order to make these long journeys, shorebirds must refuel regularly. They rely on staging areas where they can feed and rest along the way. Whenever a mudflat is lost to development or pollution, it’s like removing a gas station from the highway. Here’s an analogy: If there is one gas station every 300 miles from here to Miami, folks would have no trouble driving there. But if just one of those stations is removed, the motorist will run out of gas and fail to arrive. For better or worse, Maine’s long coast and big tides mean that we have critical shorebird staging areas. Without Maine, “you can’t get there from here.”

The bulk of the shorebird population nests in northern Canada. In the spring, they’re in a rush to get there. They follow an interior route through the United States, largely bypassing Maine. But after a stressful breeding season, the birds need the coastal fuel supply to get back south. Most of the population funnels through Maine in August and September, collecting in places such as Lubec, Thomaston, Scarborough and Biddeford Pool. Upon seeing a flock of thousands, you may think these birds are not threatened, until you realize that it’s the whole world’s supply passing in front of you and that’s all there are.

It’s daunting to open a guidebook and see how many shorebirds are pictured. Around three dozen species have been reported along the Maine coast. Many look alike. I admit that a single sandpiper standing alone might be tough for a beginner to identify. But these guys are seldom alone. They’re in big flocks that allow you to compare them to each other. Let me make this easy for you: divide and conquer.

When you hit the mudflat, divide up the flock you’re seeing into three categories: sandpiper, plover or something that’s not a sandpiper or plover.

Now, since they are the most numerous, divide up the sandpipers. Use my rule: Everything is a semipalmated sandpiper unless it’s not. Most of the small, grayish peeps are semipalmated sandpipers.

Semipalmated means that there is a little bit of webbing between the toes, which helps them walk on the mud. Least sandpipers are slightly smaller and browner, with yellowish legs. Together, they make up the bulk of the sandpiper flock on the beach.

Next, look for anything that isn’t one of them. White-rumped sandpipers are very similar but slightly larger. Since their legs are a fraction longer, look at the birds that are standing a little deeper in the water. The rare Baird’s sandpiper is the same size as the white-rumped sandpiper. An oversized peep could be either one of them. A pectoral sandpiper stands much taller than the others.

Try it with the plovers. Every plover is a semipalmated plover unless it’s not. Black-bellied plovers are twice the size. Together, they make up most of the larger peeps on the beach. Piping plovers will look different than semipalmated because they are much whiter. Sanderlings are nearly as big as black-bellied plovers but they are the color of white sand.

When you realize that most of the smallish birds are one of just four species — semipalmated and least sandpipers, and semipalmated and black-bellied plovers, life on the mudflat gets simpler. After all, you learned this game in kindergarten: “which one of these things is not like the others?” Now it should get easy to pick out the few short-billed dowitchers, red knots and ruddy turnstones in the flock, right?

Bob Duchesne serves in the Maine Legislature, is president of the Penobscot Valley Chapter of Maine Audubon, created the Maine Birding Trail and is the author of the trail guidebook of the same name. He can be reached at duchesne@midmaine.com.

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