Nesting on Bare Ground

     Northern horned larks and killdeer plovers are the only species of birds in Lancaster County, Pennsylvania adapted to regularly and commonly nesting on bare ground.  Both species are pre-adapted for rearing offspring in denuded soil because larks inhabit open ground, including prairies and tundra, and killdeer, which are inland shorebirds, live on patches of bare soil, mud flats and patches of gravel, all with little or no vegetation.  Plowed fields, which are human-made habitats in this area, as elsewhere, expanded the breeding world of both these species.  By nesting on plowed soil, these species increased their breeding potential and numbers. 
     Both the larks and killdeer are brown on top to blend into their habitat of denuded ground.  They can't be seen until they move.  And if that wasn't enough, both species have black markings around their faces to break up their shapes.  But larks are light underneath and killdeer have white chests and bellies.
     Horned larks and killdeer eat a variety of invertebrates on bare-ground fields, but the larks also eat weed seeds and grain, particularly during winter.  When snow covers the fields, larks eat chewed, but undigested, corn kernels from animal manure spread on top of the snow while killdeer retreat to seepages of running, shallow water to catch invertebrates kept active by the warmer water.  
     Both these species of open country birds lay their camouflaged eggs on the bare ground.  Larks dig shallow, tea-cup-sized nurseries in the bare ground for their eggs, but killdeer lay their four eggs right on the soil, or gravel driveways, parking lots or roofs, with no hint of a cradle.   
     Corn fields and tobacco fields are mostly bare ground when those plants are young.  If the parents of both bird species place their nests in rows of cultivated plants, the young have a chance of surviving.  But if their cradles are between rows of plants, the eggs or young may be destroyed by cultivators that dig out weeds and loosen the soil.  Some nests are destroyed by cultivation, but each pair tries again, and, maybe, again, until they hatch a brood.  But it's interesting that, maybe, future larks and killdeer will all put their nurseries in rows of plants because over the years only the young hatched in a row of plants will survive to pass on their genes.  Eggs in clutches between rows of vegetation will be destroyed before they hatch.      
     Young larks hatch practically naked, camouflaged, completely helpless and with their eyes closed, all of which keeps them from leaving the safety of their nursery.  Their parents, of course, feed them invertebrates in the nest until they fledge and feed themselves.  Newly-hatched killdeer are born fully fuzzed, camouflaged and with their eyes open.  They are ready to run to feed themselves and escape hawks, cats and other predators within 24 hours of hatching.  These two types of chick behavior are different experiments in survival on bare ground.  So far, both strategies work.
     Not even bare ground in farmland is devoid of breeding birds.  If the reader sees birds nesting on denuded soil in cropland, chances are good they are horned larks and/or killdeer plovers.