Inland Northbound Shorebirds

     During April and May, several species of shorebirds (sandpipers and plovers) migrate north through the Middle Atlantic States on their way to Canadian and Alaskan nesting grounds.  Many of those birds, which are ambassadors of their wintering grounds in South America and the Arctic tundra where they nest, move north along the Atlantic Coast, and many others migrate inland on their way north.
     But those inland northbound shorebirds have to stop to rest and eat invertebrates in temporarily flooded fields and meadows left from heavy or prolonged, spring rains, and along waterways in farmland before continuing their travels.  The sandpipers are most likely to wade in the shallows of those pools in fields and meadows or walk along their muddy edges to get food, while the plovers walk on higher, drier croplands and pastures to ingest theirs, which reduces competition for food among those related species.
     Early in April, several Wilson's snipe, which are a kind of sandpiper that winters along small waterways in agricultural pastures, are still in this area. These robin-sized, brown and dark-streaked shorebirds rapidly probe their long beaks into mud under shallow water to pull out invertebrates.
Killdeer plovers, that arrived from farther south in March, walk along the edges of those same streams in search of small critters to eat.  The snipe leave the southern part of this area by late April, but the killdeer nest throughout the region.  
     Also in April, a small variety of migrant sandpipers arrive in this area, including flocks of pectoral sandpipers, least sandpipers, greater yellowlegs and lesser yellowlegs.  These species wade in the shallows of field and meadow puddles to catch invertebrates in the mud under the water, or in the water after they came out of the ground to keep from drowning.  The two kinds of yellowlegs, which do have yellow legs, by the way, wade into deeper water because their legs are longer than those of other sandpipers that migrate inland.  Greater yellowlegs emit clamorous, melodious calls when in flight and lesser yellowlegs often fly up from feeding for no reason I can see, circle the fields and puddles, then land on them again and immediately start feeding.  
     The pectoral and least sandpipers wade in shallower water or the muddy edges of the puddles because of their shorter legs.  Leg length has reduced rivalry for food among the various sandpipers.
     Interestingly, the yellowlegs are gray, which is camouflage in the water that reflects gray skies.  The pectorals and least sandpipers are brown to blend into the color of the mud they walk on.  Least sandpipers resemble feathered mice creeping about on the mud.  Flocks of them huddle into the wind when not feeding, but often wheel up into the wind from puddles and mud for no reason apparent to us, circle the water a few times in fast, erratic flight, alternately flashing white bellies with one turn and brown backs with another, amid their own excited, rasping cries.  Then they settle on the mud again like pebbles tossed randomly across the mud, disappearing the instant they alight.  And, remarkably, they do all that without a single collision.  Their groups in wild, swift flight are perfectly coordinated with the split-second timing of each aerial turn. 
     Later in April, while the yellowlegs and other types of sandpipers are still here, spotted sandpipers move into the area to raise young, as they do across most of the Lower 48.  Spotties seek food along waterways and inundated cropland and pastures and finally settle down to hatch babies near water in those same agricultural habitats.
     Interestingly, spotted sandpipers bob and dance as they walk along water to find invertebrate food.  That action imitates debris bouncing in water, which is a form of camouflage.  And the spotties are brown above and white below, with dark spots all over, again to blend into their surroundings.
     Early in May, solitary sandpipers, semi-palmated plovers and black-bellied plovers pass through the Mid-Atlantic States in their northbound migrations.  True to their name, solitaries wander about singularly in the shallows of flooded fields and meadows and back waters of streams to catch tiny critters to eat.  Solitaries are dark-gray on top with many light spots to blend into the shadows under tree limbs hanging over shallow water.  They have a dainty flight; buoyant like that of butterflies. 
     Solitaries are the only sandpiper in North America that nest in other birds' nests in the tops of spruce trees in Canada's boreal forests.  They nest in that niche because the eggs and young are away from ground predators.  The four, newly-hatched chicks must leap from their nests to the ground to be able to find invertebrate food.    
     Semi-palm plovers and black-bellied plovers generally walk through plowed fields and other denuded ones in their quest for tiny creatures to consume.  Their doing that reduces competition for food with their sandpiper relatives.  Neither plover species is common here and are thrilling when spotted during their May migration north.
     Eventually the water from spring rains seeps away and the migrant shorebirds continue north to their breeding territories.  But those sandpipers and plovers were thrilling to see while they were here, however short their stay.  I think it's exciting to see wildlife living in habitats we people created for ourselves.  Long live adaptable life.