Adaptable, Inland Ring-bills

     The leisurely, direct and powerful flight of ring-billed gulls is poetry.  Their graceful soaring on high on long, supple, swept-back wings is a natural masterpiece of elegance.  Tipping this way and that on black-tipped wings to make mid-air turns, whirls of many ring-bills search for winds and thermals that will carry them higher and higher with perfect ease and grace.  And adaptable as they are beautiful in flight, ring-bills are lovely, interesting additions to inland, human-made habitats, including land fills, blacktop parking lots, bare-ground fields and extensive lawns, where they get much of their food through each winter.  Those gulls are pre-adapted to those built, open habitats because they evolved on coastal beaches, mud flats and salt marshes.  And because of their adjustments to human-made environments and activities, they have increased their numbers greatly in recent years.
     Hundreds of thousands of ring-billed gulls winter in the Middle Atlantic States because of the Delaware and Susquehanna Rivers, the upper Chesapeake Bay and several inland, human-made impoundments, including the Octoraro Lake, Struble Lake and Blue Marsh Lake, where they roost overnight on water, or ice, and mid-river boulders.  And every winter morning, long, straggly lines, "V" formations and scattered bunches of ring-bills leave those waters and power gracefully across the sky to feeding areas, particularly landfills these days. 
     Blizzards of swirling white and pale-gray ring-bills settle on landfills in the Mid-Atlantic States to consume edible garbage, along with swarms of starlings, scores of vultures of two kinds and flocks of American crows.  The gulls are so sure of their ability to take flight when necessary and used to the big trucks bringing in garbage, that they swarm in flight all around those huge vehicles as they dump garbage in the landfills.      
     The adaptable ring-billed gulls have other sources of food through each winter.  They plunk down on blacktop parking lots to ingest French fries, bread crumbs and other edibles thrown out by careless humans.  And they eat earthworms and other invertebrates off bare-ground fields, extensive lawns and country, blacktop roads, particularly after heavy or prolonged rains. 
     In November and March, when local soil is likely to be soft enough for plowing, many ring-bills associate that plowing with food and drop to the fields to ingest it.  They land in furrows behind the forward-moving plow blades to grab and consume exposed earthworms and other invertebrates.  Amid much flapping and calling, flocks of ring-bills form "pinwheels" of themselves as gulls in the back of the trenches fly forward, over their fellows in the furrows and drop into the ditches right behind the blades.  Those bustling crowds of ring-bills, frantically competing for a limited food supply, make interesting, natural spectacles in our local fields.           
     Before impoundments freeze, ring-bills catch small fish from their surfaces.  But when those still waters become glazed with ice, those gulls concentrate over turbulent waters that rushed down through turbines in hydroelectric dams on the Susquehanna to catch small fish that went through those turbines and welled up in the turbulence below each dam, either dead, injured or dazed, and easy pickings for the gulls.  Great clouds of ring-bills swirl back and forth low over the agitated water, without collision with their feathered fellows, as each bird watches for vulnerable fish to grab in its beak and eat.     
     Some ring-billed gulls are pirates at times.  They try to steal fish from common merganser ducks, pied-billed grebes and other diving, fish-eating birds that surface to swallow their catches.
     Ring-bills, like many kinds of gulls, scavenge dead fish when that food is available on the water's surfaces and along shorelines.  It's this looking for a variety of foods in a diversity of habitats that helps make ring-bills successful and abundant.  Adapting is a key to success.
     Ring-billed gulls are a large part of the Middle Atlantic States' wintering avifauna in open, human-made habitats because of the gulls' being preadapted to them.  They are beautiful in flight, and highly successful in using built habitats, making them an abundant, intriguing species here in the Mid-Atlantic States.