Changing the Flying Guard

     From about 8 to 9 pm for several evenings from the second week in July to the second week in August of 2015, I watched the changing of the flying guard in a Lancaster County, Pennsylvania suburb.  I saw several kinds of creatures in the sky each evening, birds and insects at first and then bats, all of which were interesting, especially the bats. 
     While sunlight was still showing, I would see several chimney swifts careening and swooping left or right on swept-back wings after flying insects.  And, occasionally, I saw a barn swallow or two.  The swallows have thinner bodies and wings than the swifts.  Most of the local swallows hunted flying insects over farmland, including on the edge of the suburb.
     As I watched the swifts and swallows doing aerial acrobatics in the evening sky to catch flying insects, other creatures were noticeable in and above the lawns.  In July, hundreds of male fireflies came out of the grass at dusk and flashed their cold lights.  Northern cardinals and gray catbirds sang in the early part of July, while a few house finches perched on the very tops of a few tall Norway spruce trees.  And as each evening wore on, several robins went to roost in neighborhood trees.
     There were a couple of unusual happenings over that neighborhood as well.  One evening I saw three great blue herons fly majestically in a line from west to east.  And on another evening, I saw a sharp-shinned hawk zip into a Norway spruce to avoid the dive-bombing of up to 20 swifts.  I didn't know there were so many swifts in that neighborhood until that time.
     By late July, I heard the courtship trills and chants of at least a few kinds of male tree crickets that were invisible in the trees and shrubbery.  Crickets, katydids and grasshoppers rub their wings, or wings and legs together, depending on the species, to make the stridulations essential to bring the genders of each species together for mating.
     And then, finally, at dusk, the main attraction, the bats, zipped and swooped over the neighborhood to catch flying insects.  Most of them came from one direction, one to three or four at a time, evening after evening, as if from a roost that I never could find (just as well).  Time after time, I estimated close to 20 bats careened over that suburb on their way to feeding areas.  Then they would scatter and the sky became too dark to see them anymore.  They were either little brown bats or big brown bats: I couldn't tell which.  
     Bats are mammals, with fur, milk and warm blood.  And they are the only mammals that can truly fly, making them entertaining in the sky.  Bats in this area feed only on flying insects.
     Bats can "see" prey and objects  around them by hearing the echos from their own constant squeaking and forming mental pictures from those echos.  The squeaks go out, bounce off objects and return to the bats' ears.             
     Each evening in July and August, the chimney swifts and, later, the bats were interesting and entertaining as they swirled and dove in mid-air after their prey.  Nothing is as beautiful and intriguing as nature, no matter where it is.