By Chet Meyers
Many birders do not think of Minnesota -- more than a thousand miles from the Atlantic or Pacific shores -- as a prime place for finding shorebirds. Birding for shorebirds is more typically associated with balmy ocean beaches and nervous sandpipers chasing the edges of curling surf. Yet each April, the first northward-migrating shorebirds show up on lakeshores and mudflats across Minnesota.
Minnesota is a great place to view more than 30 species of shorebirds. They stop in our state on their way to arctic breeding grounds and stop again in late summer when returning to southern wintering grounds, which stretch from the shores of Texas to the southern reaches of Argentina. And shorebirds are such cooperative birds to view. Most seem downright lethargic in their foraging habits, particularly when compared to tiny warblers that constantly flit out of sight. Shorebirds allow birders plenty of time to focus binoculars or spotting scopes, and often allow viewing at close range.
Identification can be a bit trickier, however, since several shorebird species closely resemble each other. Birders can make a positive ID with a little knowledge about shorebirds' migratory timing, foraging habits, basic body shape -- and even by getting a good look at their legs and bill.
For birders, the term shorebird refers to a diverse group that includes sandpipers, plovers, stilts, avocets, oystercatchers, turnstones, phalaropes, and even snipes and woodcocks. They are a group of generally drab-plumaged birds that spend much of their time foraging along ocean beaches, lakeshores, and wetland mudflats. Shorebirds typically feed by probing the mud, pecking prey from the water's surface, or skimming shallow waters for small crustaceans and larval insect forms.
Shorebirds range in size from the long-billed curlew -- as large as a crow -- to the sparrow-sized least sandpiper. Though short-legged compared with wading birds such as great blue herons or great egrets, shorebird species vary quite a bit in leg length. Not surprisingly, the greater yellowlegs is known for its relatively long yellow legs. The least sandpiper has fairly short legs.
The characteristically pointed bills of shorebirds also vary by species. The marbled godwit sports a long, upturned bill. The pectoral sandpiper's bill is medium length and downturned, or decurved.
While a few shorebirds nest in Minnesota, most species are just passing through. They raise their young on the arctic tundra and then, relatively quickly, turn around and head south; many male shorebirds begin their southward migration less than two months after arriving on the breeding grounds. In Minnesota the so-called fall migration of shorebirds actually starts in mid-July as birds travel to wintering grounds in the southern United States and throughout Central and South America.
In spring in Minnesota, the northward shorebird migration begins in mid-April (or as soon as lakes have thawed and shorelines are free of snow) and peaks about the middle of May. Early migrants include the marbled godwit, greater yellowlegs, pectoral sandpiper, least sandpiper, and long-billed dowitcher.
Almost any extensive shoreline, mudflat, or even flooded field will attract some shorebirds. Birders frequent a number of other favorite spring places. Park Point in Duluth can be a shorebird hot spot, though the interior of northeastern Minnesota has little shorebird stopover habitat. In mid- to late April birders gather at Salt Lake, which straddles the Minnesota-South Dakota border. This shallow 312-acre lake and its alkaline waters produce an abundance of brine shrimp and other zooplankton that attract an amazing number and variety of shorebird species, including rarities such as the piping plover, red phalarope, and ruff. The Salt Lake Wildlife Management Area in Lac qui Parle County has a sturdy viewing deck.
In recent years many national wildlife refuges, such as Agassiz NWR in northwestern Minnesota and Big Stone NWR near Odessa, have intentionally drawn down some of their wetland pools to provide mudflats where shorebirds can recharge their batteries by feeding on tiny crustaceans and other prey. The western end of Lake Byllesby in southern Minnesota has been a hot spot in recent years for a wide variety of shorebird species.
In the Twin Cities, a newly developed hiking trail at the Purgatory Creek wetlands in Eden Prairie can be bountiful with shorebirds so long as water levels are low and mudflats are exposed. Last year more than 20 species showed up there between April and June.
Shorebirds turn up in some places seldom visited by most Minnesotans: Sewage ponds are rich in shorebird prey. A Birder's Guide to Minnesota, by Kim Eckert, lists 243 sewage ponds around the state, including several near Thief River Falls. In southern Minnesota, the Sleepy Eye sewage ponds often draw rare shorebirds that bring birders flocking from across the state. Recently some sewage ponds have been closed to the public, but most municipalities are tolerant of birders. Contact the appropriate chamber of commerce about permission to enter a sewage pond area.
Sod farms are also promising places to spot shorebirds. When sod is stripped, acres of mud are exposed -- creating a de facto mudflat, especially after spring rains. Buff-breasted sandpipers and American golden-plovers actually prefer sod farms to mudflats. Birders at a sod farm should be considerate of the farm owner and view birds carefully from the roadside.
Shorebirds travel in flocks, which makes for convenient viewing. On a good spring day, lakeside mudflats can easily hold eight to 10 species. Smaller birds usually feed along the water's edge, while large birds often wade out belly-deep, probing beneath the surface.
When shorebird watching, I carry my regular 8-power binoculars to locate the birds and a 30-power wide-angle spotting scope to focus on them. With a good spotting scope, I can compare size, shape, and behavior for clues to identify the most confusing species. But a spotting scope is not essential for beginning birders, just binoculars and some knowledge of shorebirding basics.
Size, bill length and shape, and leg length and color are good starting points for shorebird identification. Bill length and shape -- straight, upcurved, or decurved -- are particularly important. Leg colors include bright yellow, yellow-green, green, steel gray, black, and shades in between yellow and black. Calls, behavior, and posture are also keys to identification.
Usually both sexes of the same species look alike. And even in breeding plumage, most spring shorebirds come in mottled browns, grays, and whites. The American avocet is quite a striking beauty. Commonly 18 inches in length, the avocet has a cinnamon-orange head, neck, and breast, and a long, narrow, up-turned bill.
Another easy bird to spot is the noisy killdeer. It has a brown back, a white neck and breast, and two distinctive black bands across its chest. But the key to identity is its strident and often drawn-out call, kideeah kideeah, kideeah, as it flies low over the ground. This shorebird, however, spends little time on the shore and is more common in open short-grass fields and even on ballfields and golf courses.
Two other easy-to-identify spring migrants are the black-bellied plover and American golden-plover. Both are between 10 and 12 inches in length and have relatively short blunt bills, like all members of the plover family. As adults, their solid black face, neck, and chest make them standouts in the shorebird clan. The black-bellied plover has pure white undertail feathers; the undertail of the golden-plover is black. Both plovers have black-and-white spotted backs, but the golden-plover also has beautiful gold flecks in its plumage.
The greater and lesser yellowlegs are also common spring migrants. Long bright-yellow legs characterize both. Their gray-and-white spotted plumage is similar, but the greater is more than 3 inches longer than the lesser. They are easiest to identify when standing side by side, but that's a rare occasion. A key difference, though a bit subtle, is the longer upturned bill of the greater yellowlegs and its three- to four-note call. The lesser yellowlegs has a two-note call.
The smallest spring shorebirds that visit Minnesota include four sandpipers -- least, Baird's, white-rumped, and semipalmated -- all barely larger than a house sparrow. They are part of a group of diminutive shorebirds often referred to by birders as peeps. One stands out from the rest: the least sandpiper, which has muted yellow legs (if not covered with mud). The other three species have dark-colored or black legs.
After a few outings of watching shorebirds, the initial confusion will begin to melt away. Soon, birds that look different will become more obvious. Last fall, while scanning a shorebird-rich mudflat in Dakota County, I shouted to my wife, "Here's a strange one!" I rushed back to the car for my Sibley Guide to Birds and paged furiously through it. The bird's plump shape and smooth gray plumage were the tip-off. But I had to check its bill and legs. Straight blunt bill...check. Short greenish legs...check. And yes, after 15 years of shorebirding, I was looking at my first red knot. What a treat! A good, clean identification.
As for the small dark-legged peep feeding beside the red knot, well, at least I knew it was a sandpiper.
A good first guide for birders seeking shorebirds is the small, compact Beginner's Guide to Shorebirds by Donald and Lillian Stokes. If you really get hooked on shorebirds try The Shorebird Guide by Michael O'Brien, Richard Crossley, and Kevin Karlson.