A guidebook is a great tool for identifying birds. It’s also pretty good at identifying birders. For instance, I can tell casual birders just by opening their books. The pages that help identify feeder birds are smudged and dog-eared, but the pages with shorebirds are bright, shiny and completely unused.

Who in their right mind wants to identify shorebirds?

Not coincidentally, this week is the apex of shorebird season in Maine. Tens of thousands of birds that nested in the far north, near or above the Arctic Circle, are now flooding our coastline en route to their wintering grounds. It’s a natural phenomenon that we often take for granted. Maine has big tides and huge mudflats.

I cracked open one of the field guides and noted 34 species of shorebirds that might be found in Maine – a big number that could leave anyone hopelessly confused. But wait. Many of those shorebirds aren’t found at the shore. The list includes American woodcock, which wouldn’t be caught dead on a mudflat. The Wilson’s snipe haunts marshes. I rarely see a Maine upland sandpiper away from blueberries, etc.

The truth is, only half of the shorebirds in the guidebook are actually found at the shore. Whew. Suddenly it’s easier. Many of the remaining mudflat birds are rather large, some as big as a pink flamingo lawn ornament. They really aren’t that tough to identify.

It’s the little ones that cause all the trouble. You can quickly eliminate semipalmated plover from the trouble category. They are small and numerous on Down East mudflats, but they’re also unique. They look like a miniature killdeer, but with one black neckband instead of two. Piping plovers are similar, but they are rare north of midcoast Maine. In short, all small Down East plovers are semipalmated plovers. Exceptions are extremely rare.

No, the trouble is sandpipers. There are five small ones that are collectively referred to as “peeps.” Yes, because they peep a lot. They all look alike, sort of. Master the differences, and suddenly the rest of the shorebird family gets easier.

Fortunately, two of them are so numerous, they quickly become easy to figure out. Over 90 percent of the mudflat sandpipers are just these two species: least sandpiper and semipalmated sandpiper. The least sandpiper is the smallest sandpiper in the world. The semipalmated sandpiper isn’t much bigger. The former is brown, with yellowish legs. The latter is grayer, with dark legs. They mingle on the mudflat, and after you’ve seen several hundred of them together, there’s not much guesswork left.

The other three are not very easy, but also not very numerous. If you failed to spot and identify one, would your life change that much? Why worry? Better to make a game out of it and try to find one, just for sport.

Western sandpipers barely wander into Maine. I’ve seen one in the last four years. True to the name, they are western birds that mostly bypass our state and head for the Florida beaches to winter over. They are only a smidgeon bigger than semipalmated sandpipers, their bills are a little bit thinner and the bill tips are slightly downturned. Their backs have a ruddy chestnut color that is absent on semipalmated sandpipers. Otherwise, the two species are nearly identical, dagnabit.

The remaining two peeps are a little larger and have longer wings. When standing on a mudflat, their wingtips extend beyond the tail. Of these two, the white-rumped sandpiper is much more common. It is so named because it does not have the black stripe down the rump and tail that other sandpipers do. It does have little dots, or chevrons, lining the top of the breast under the wing. It’s longer-legged, with the habit of sticking its rump higher into the air while feeding – quite noticeable.

Baird’s sandpiper is a grassland bird on its mid-continental breeding range. A few get over to Maine each fall in migration. They’re as likely to be found on sod farms and sewage lagoons as mudflats. They also have wings longer than the tail. They are a little browner, and their backs often have dark, diamond-shaped marks that set them apart from the similar-sized white-rumps.

So, if a mudflat is in your future, let’s set aside the panic that small sandpipers are hard to identify and not worth the effort. Almost all of them are least and semipalmated sandpipers. Finding the other three? That’s like panning for gold. Every now and then, you’ll find a nugget.

Bob Duchesne, Good Birding

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.