Sorting Out Sandpipers

semipalmated-sandpipers_chicobasinranchco_20100501_lah_4500Late August is one of my favorite times to go birding. Maybe that’s because I really like shorebirds. I grew up near the beach, and studied marine biology in college—and I still get excited about anything to do with the ocean. The shorebirds here in Colorado are nowhere near a coastline, but they’ll have to do, at least for now.

The calendar may still say summer, but shorebirds consider this time of year to be fall. They’ve finished nesting, and it’s time to head someplace where winters are warmer. Many species breed in the arctic, and Colorado is right on their route south.

The best place to hunt shorebirds, of course, is near water. Different species prefer different depths, largely according to the length of their probing bills and stilt-like legs. Bodies of water with shallow beaches are best, where the birds can wade out as far as they want; they tend to shun abrupt edges. They’re seeking insects, crustaceans, worms, and other invertebrates to fill their crops, so long-established lakes and reservoirs will be more productive.

Of course, the real challenge birders face with non-breeding shorebirds is telling them apart. At first glance, they all appear alike: tan on top and light underneath. You won’t be able to identify these birds by their color.

wilsons-plover_caborojonwr-pr_20100527_lah_4747I still struggle with naming medium-sized sandpipers, but I have learned a few things that help. First, make sure they’re sandpipers. Stilts, avocets, plovers, and phalaropes are all similar in appearance, and occupy the same habitat. Happily, silts and avocets have distinctive plumage, so they’re easy to eliminate. Plovers (like the Wilson’s Plover in the photograph) have much shorter, stubby bills, and the smaller ones look like beach stones on legs. Phalaropes avoid land, and can be spotted by their unique feeding behavior—swimming in tight circles to stir up food from the bottom.

Once you’ve weeded out the other shorebirds, look at the relative size of the sandpipers. Dimensions can be hard to estimate, but if there is more than one species present, you can at least sort them from larger to smaller. Most field guides are arranged that way, with the largest sandpipers first and the petite peeps at the end.

marbled-godwits_chicobasinranchco_20100501_lah_4314Now look at the bill. Is it straight, or does it go up or down at the end? Is it all one color? How long is it compared to the rest of the bird? For being fairly small birds, Dowitchers have extremely long bills. Whimbrel bills are long and Curlews’ are even longer; both turn down at the end. Godwits, as shown here, have bills that turn slightly upward and are two-toned.

ruddyturnstone-florida-keys-1jan08-lah-852If you can see the birds’ legs, try to determine the color. Yellowlegs aren’t the only sandpipers with yellow legs. Leg color is the easiest way to separate out a Least Sandpaper from the look-alike Semipalmated (photo at top) and Western Sandpipers. Redshanks are named for their red legs,  Willets have legs of steel gray-blue (they look cold to me), and this Ruddy Turnstone sports bright orange legs. Check where the birds are walking so you aren’t misled by a coating of mud.

Hopefully, you’ve narrowed down your choices considerably by this point.

Next, think about where the birds are feeding. Are they on shore, or barely getting their toes wet? Or are they out in deeper water? Some species tend to stick to the shallows, while others venture out farther from shore. Watch them feed for a bit. Dowitchers have been likened to a sewing machine, with their rapid up-and-down head movements.

semipalmated-sandpiper_caborojonwr-pr_20100527_lah_4919If you’re lucky, the birds might take to the air, so you can see the patterns on their wings and tails. It’s even better if they say something. The best way to differentiate between short- and long-billed Dowitchers is by their calls. The same holds for Greater and Lesser Yellowlegs.

Finally, consider where you are birding. While any bird can get lost, especially juveniles migrating for the first time, it’s more likely, for example, that you’ll see a Western Sandpiper in California and a Semipalmated Sandpiper in the east.

Be sure to look at every bird in a flock. Species tend to mix. You could be looking at 99 birds of one kind, and the 100th bird will be something totally different—perhaps even a new lifer.

Don’t get frustrated if you can’t identify every bird you see. Be patient, practice, and hang out with birders who are more experienced. It helps to have more than one field guide handy, as illustrations vary. Kenn Kaufman’s Advanced Birding is very useful as well. Sandpipers are tough birds to learn. Maybe, when you get really good at it, you can help me with some photos I still can’t place with confidence.

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