EARLIEST SOUTHBOUND SHOREBIRDS AND SWALLOWS

      During July and into August, a variety of shorebirds and swallows are some of the first birds to migrate south to escape the northern winter.  Least sandpipers, semi-palmated sandpipers, greater yellowlegs, lesser yellowlegs and semi-palmated plovers are, generally, the first shorebirds to leave their Arctic tundra nesting areas and arrive in the Lower 48, including Lancaster County, Pennsylvania.  And, during that time, local purple martins, barn swallows and tree swallows, all swallow species, are gathering into flocks to drift south.  

     The first shorebirds arrive in Lancaster County by the middle of July and settle on the mud flats and shallows of human-made impoundments, and certain, low-lying, flooded fields and meadows of local farmland.  There they alternately rest, and feed on invertebrates they pull out of the mud and inch-deep water to build up their weight and strength for the next part of their southward migrations.  Least and semi-palmated sandpipers and semi- palmated plovers usually walk across the mud flats to ingest invertebrates, while the two yellowlegs species wade in the shallows to snare invertebrates.  By getting food in different niches, these shorebirds are not competing directly with each other for food, which is helpful to all species.  

     All these shorebirds are difficult to spot in water, and on mud flats and flooded fields because their feathering blends them into their niches.  People usually can't see them until they move or fly up and away.  Being camouflaged protects them from peregrine falcons, merlins and other kinds of predators.  The yellowlegs have gray feathering, mostly, which camouflages them in water.  And the other types of early shorebirds are brown on top, which blends them into their mud niches. 

     Having evolved on tundra, mud flats and beaches, these shorebirds are well adapted to built impoundments, and certain low-lying fields and meadows.  Fields and meadows these shorebirds are attracted to have little or no vegetation when the birds migrate over them, making those human-made habitats resemble the flats and beaches shorebirds are used to.  

     Shorebirds are particularly exciting to see when groups of them sweep low, turning together this way and that, time after time, over mud flats, impoundments and fields.  Sometimes they are stirred into flight by a passing falcon, or for reasons unknown to me.  Eventually, however, they swoop down for a landing, like peanuts being tossed across the flats or fields. 

     During the latter half of July, martins and barn and tree swallows, that nested in Lancaster County,  gather into groups of their own in preparation for drifting south to escape the northern winter.  All these swallow species, often by the scores or hundreds, line up on roadside wires and in trees between feeding forays over fields, meadows and impoundments after flying insects to fatten up on.  But they are most fascinating, entertaining and inspiring when sweeping in loose flocks low over fields,  pastures and impoundments, weaving among each other in swift flight, after their meals.  And beyond that, it is most intriguing to see swallows foraging across the sky, while shorebirds are feeding on critters they pull from mud flats and shallows below the swallows.  The two families of birds feeding at the same time is most entertaining and inspiring.    

     Each family of birds is built for what they do.  Shorebirds have long beaks they poke into soil to pull out invertebrates.  And some shorebirds have long legs for wading into water after their food.  Swallows are small with tiny legs to reduce weight, have wide mouths for catching insects on the wing and long, powerful wings for fast, erratic flight after their airborne prey.   

     Suddenly the local flocks of swallows are gone; martins being the first to depart by late July.  But all these swallow species are soon replaced by other swallows of their kinds that nested farther north and are drifting through this area on their way south, feeding on flying insects and creating more entertainment and inspiration as they go.  

     Each family of these birds is built for what they do, in different niches from each other.  Neither family can feed the way the other one does.  Shorebirds feed on invertebrates they probe for in mud and water.  Swallows only consume flying insects above mud and water.  Therefore, those families of birds can live in harmony in the same open habitats.  

     During late summer, look for these birds in farm country throughout the United States.  They are entertaining and inspirational, especially when seen together.                

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