Foraging Killdeer and Larks

     One late morning at the end of August, I was driving home through Lancaster County, Pennsylvania farmland after doing errands.  Driving by a field of alfalfa stubble left from "making hay", I saw a few killdeer plovers on it and then a few more killdeer.  I drove in reverse back the rural road I was on to the end of the field and then drove forward slowly to count the killdeer among that stubble.  I stopped every so many yards to count the plovers, with the aid of 16 power binoculars, in the field off to the side of my car.  Those birds walked and stopped, walked and watched for any invertebrates they could consume.  When stopped briefly, I saw a few killdeer catch critters from among the stubble and swallow them.  At the end of the hay field, I counted 46 killdeer plovers, which was a nice-sized, post-breeding group.  By August, the young of the year look like their parents and all killdeer, young and older, gather into groups for mutual protection as they feed.
     Driving on another two miles, I noticed several small birds and a few killdeer in a meadow with grass that was nipped close to the ground by horses.  I was on another country road with little traffic, so I stopped to identify the small birds.  They were northern horned larks; about 20 of them mixed with six killdeer.  And all those birds were foraging for invertebrates among the short grass and on the soil.         
     Killdeer are the size of robins while horned larks are sparrow-sized.  But they have traits in common because they share open-ground habitats, including bare soil, and those with short or sparse vegetation.  Both species are brown on top, which allows them to blend into their habitats to the point of being invisible until they move.  The plovers have two broad, black rings around their necks that break up their body shapes, which helps camouflage them.  The larks have black bibs and a black side-burn below each eye that helps disguise their body shapes, confusing would-be predators.
     Both these common species raise young in Lancaster County farmland, as well as on open-ground habitats across most of North America.  Killdeer are inland shorebirds that lay four white, dark-speckled eggs in a clutch directly on gravel or bare soil without the slightest notion of a nest.  Their fuzzy, camouflaged, open-eyed young are able to run about and feed themselves within 24 hours of hatching, which is good on open ground.
     Horned larks dig tea-cup-sized cradles in bare soil in fields where they lay up to five eggs per clutch.  The chicks hatch blind, practically naked and helpless, and must stay in their nurseries for about 12 days before fluttering into the surrounding fields.  But these chicks lie still, are camouflaged against the soil and fed in the nest by their parents.  Recently fledged chicks have dark-brown feathering, spotted with white, which makes them invisible in the fields. 
     Killdeer and lark nests in fields could be destroyed by plowing or cultivation.  If that happens, the pairs of each species try again and again until they successfully raise at least one brood a season.
     Killdeer plovers and northern horned larks are the only kinds of birds that raise young on bare ground in Lancaster County cropland.  And in late summer and autumn, both species gather into flocks of themselves in those same fields to forage on the abundant invertebrates, put on fat and get ready for the coming winter.  And they have to move around the farmland as machinery harvests crops in those agricultural areas.  But these are hardy, adaptable birds that were long ago pre-adapted to open ground.  They make use of a habitat that few other bird species can, adding more intrigue to the farmland they live on.