Back in the day when horses were our main form of transportation, the chipping sparrow was called the hair bird because horse hairs were often found woven into their nests.  Nowadays since horses have given way to cars, chipping sparrows rarely use horsehair to construct their nests anymore.  However, deer and cow hair are sometimes found in the nests of this common sparrow.

        From now into autumn, untold millions of birds that nested throughout North America will be migrating southward to their wintering grounds.  In fact, approximately 75 percent of the birds that nest across the length and breadth of the continent migrate.

       Some of the migrants that nest in our backyards include the gray catbird, orchard oriole, Baltimore oriole, barn swallow, tree swallow, chimney swift, summer tanager, great crested flycatcher, wood thrush, and ruby-throated hummingbird.

       The brown-headed cowbird does not build its own nest or raise its young.  Instead, it lays its eggs in the nests of other birds and leaves the arduous job of raising its young up to them.

       The brown-headed cowbird lays its eggs in the nests of more than two hundred species of birds.  The list of birds parasitized by this nest parasite includes backyard favorites such as northern cardinals, brown thrashers, and northern mockingbirds.

       In many cases, although their eggs look very different from the eggs of the unsuspecting host birds, the hosts accept them as their own.  As such, they end up raising cowbird hatchlings along with their own young.

       Interestingly, gray catbirds are rarely parasitized by brown-head-headed cowbirds.  Biologists believe this is because, unlike far too many birds, catbirds seem to be able to distinguish color and size differences between their own eggs and those of the cowbird.  As such, when a nesting catbird discovers a brown-headed cowbird egg in its nest, it unceremoniously removes it.