On Aug. 25 at a high school football game on Wheeling Island in the Ohio River, a flock of high flying birds distracted my attention from the game. Shortly before sunset, I counted about 50 common nighthawks swirling and feeding above the stadium lights.
I watched until they disappeared in the darkening night sky.
About the size of a robin with longer, narrower wings, nighthawks are charcoal gray with a single bold white bar on each wing. Evening flocks of nighthawks in flight are just one of many signs of the transition from summer to fall.
City dwellers should also keep their eyes peeled for flocks of chimney swifts. As they assemble in large pre-migratory flocks, they attract attention when they go to roost each night about the same time nighthawks circle overhead.
Their constant twittering is difficult to ignore as they swirl above the chimneys where they will spend the night.
Sometimes swifts circle for 15 to 20 minutes before one bold soul breaks from formation and descends into the chimney. Others quickly follow. If the flock is large, the image suggests a plume of smoke returning to the chimney.
Inside the chimney, these birds, which resemble flying cigars, sleep while clinging tightly to the chimney wall. Once upon a time, they roosted inside huge hollow trees. Today such trees are rare, so swifts use man-made chimneys.
For swift enthusiasts all across the U.S., the Driftwood Wildlife Association (1206 West 38th, Suite 1105, Austin, TX 78705) sponsors a citizen science program called “A Swift Night Out.”
It works like this: On one night next weekend (Sept. 9-11) watch the skies at dusk and look for feeding flocks of swifts. Then when they go to roost, count the number of birds that enter the chimney. Then submit the time, date, location and number of swifts to DWA@austin.rr.com.
Results from the first 10 swift censuses can be found at www.ChimeySwifts.org.
By day, I see even more evidence of seasonal change. Juvenile goldfinches have joined the adults on my finch feeders, and some adult males have already begun to lose their golden glow.
In fields and along country roads, late summer wildflowers bloom. Every patch of ground that escaped the mower’s blades is covered with plants that reach well above my head.
Bright purple ironweed and lavender Joe-Pye-weed attract dozens of tiger swallowtails, monarchs, fritillaries, and skippers. Roadside stands of nectar-bearing jewelweed provide natural food for hummingbirds preparing to migrate.
I’m already noticing fewer adult male hummingbirds, the ones with the ruby red throat. Adult males began to leave in mid August, and any males I see now are migrants from further north. Adult females and juveniles began heading south last week.
But throughout September migrants from points north will continue to pass through and visit nectar feeders. So keep your nectar feeders filled until mid-October.
Shorter days, not a dwindling food supply, trigger hummingbird migration.
I never take my nectar feeders down until I go 10 days without seeing a hummer. That usually takes me into early October. And if you keep one feeder up until Thanksgiving, you just might see a rufous hummingbird, a western species that has been showing up throughout the east with increasing frequency each fall.
Maturing pods of milkweeds are another sure sign of summer’s end. Keep an eye on them, and when they split, collect the silky parachuted seeds to plant next spring. Monarch butterflies will thank you by laying eggs on the spring growth.
As I walk the edge of the yard, I notice pokeweed towering two feet above me. Fruit-eating birds such as robins, bluebirds, catbirds, and brown thrashers devour the deep purple berries and disperse the seeds through their droppings.
And the last blooms of summer — goldenrod and asters — add splashes of color to the hayfield on top of the ridge.
The beginning of September is a time of ecological transitions. Listen for night migrating song birds as they pass overhead.
Watch for nighthawks and chimney swifts at dusk and lines of southbound monarch butterflies all day long. And say good bye to ruby-throated hummingbirds as their numbers dwindle to nothing by the end of the month.
(Send questions and comments to Dr. Scott Shalaway, RD 5, Cameron, WV 26033 or via e-mail at his website, http://scottshalaway.googlepages.com.)