As the long days of summer start to shorten and the fall evenings grow cooler, many of our local birds start to move south for the winter. If you get the chance, go outside in the early evening and scan the darkening skies. You should start to see the beginnings of the Common Nighthawk migration that passes through our area of the country.

From the last few days in August through the end of September, large numbers of these very impressive birds enliven the evening skies with their distinctive shapes.

The Common Nighthawk is a member of a large, worldwide family that includes the nightjars of Europe and Asia, and the Whip-poor-wills and Chuck-wills-widows of the US, Central and South America.

Most, if not all, of these cryptically-colored species are nocturnal, but the nighthawks are also visible in the evenings and sometimes throughout the daylight hours. They can sometimes be found roosting lengthwise along branches or power-lines or perched on top of wooden fence-posts. If disturbed, the birds bound off like large brown moths only to settle again a short distance away.

The Common Nighthawk is about 10 inches long, around the size of the familiar American Robin, but is completely gray-brown in coloration. Its wings and tail have white panels on their tips, which appear like white holes in the birds wing feathers.

In flight, the nighthawks are unmistakable as they lurch and veer around chasing their favorite food of large moths and other insects. The birds bounce around in a most peculiar manner appearing to be on the end of a piece of string that is being tugged at irregular intervals.

Common Nighthawks, or to use their local name of Bullbats, are found throughout the Carolinas during the breeding season, but their range is rather disjunctive, and birds are often absent from seemingly suitable areas.

If you have never seen and enjoyed these birds, now is the time to get outside and really enjoy the southbound passage of nighthawks as they pass over in the evening sky. Some days it may be possible to see hundreds of them as they wheel overhead feeding on their way south to the grasslands of southern South America.

Simon Thompson has lived in WNC for the past 16 years. He owns and operates his own birding tour company, Ventures Birding Tours. www.birdventures.com.

If you have birding questions, please drop Simon an e-mail at the above site.