Wings in the Night

Bird Cast

My electronic calendar reminds me it is the autumnal equinox and the first day of another season. Wildlife has its own calendars and clocks. The hummingbirds who pay hourly visits to our feeders didn’t turn up today. I saw only one Osprey flying over Powhatan Creek last week and it has probably left to join others in balmy Caribbean waters.  Purple Grackles and Red-Winged Blackbirds are flocking, and other feathers are flying, though mostly unseen.

Bird migration has held me in thrall since senior student days long ago. I gave a nervous presentation to my department about a new Science paper that conflicted with the theories of one of our professors sitting in the front row. We know why migration happens, and expect it will be impacted by climate change, but how birds navigate thousands of miles, sometimes traveling as lone juveniles, is still poorly understood.

If a bird’s brain seems too small, how can an insect’s brain manage the task? We still have Monarchs filling up with nectar from Mexican sunflowers and Lantana. This last generation of the year will head to their wintering grounds in Mexico. To coin an overused word because I can’t think of a bigger one—the feat is AWESOME.

If you are curious about local bird migration, I suggest googling Bird Cast. This tool was created by the Cornell Lab of Ornithology and academic partners using radar technology to detect flocks of migrating birds across the continent.

When I visited the website on September 11, it recorded 546,000 birds crossing my county (James City) the night before. The peak number was 51,000 at 11.10 PM. They traveled at an average speed of 16 mph and at 2,600 ft. Migration mostly occurs between dusk and dawn to avoid predators and rest and feed in the daytime. Only 78,100 birds traveled overhead last night, but migration will continue for many more weeks. Bird Cast doesn’t identify species (pending refinements from AI and machine-learning), but, based on other observations, the flocks probably included warblers, flycatchers, tanagers, orioles, and thrushes.

At this time of plenty, farming communities traditionally celebrated bringing in the harvest. Vivaldi represented it with zest from violins in his suite, The Four Seasons. Birds are busy, too, fattening up before a journey that depletes energy reserves and knowing that staying behind is courting starvation in winter. The violins play a mournful largo for that season when the countryside sleeps and our birds sing to foreign ears.

First swallow of spring

Tree Swallow
Tree Swallow. Photo: Patrice Bouchard, Unsplash

On the last day of winter, I saw my first Tree Swallow of the year. It flew beside the James River in the direction of Jamestown Island.

Sociable birds with an iridescent sheen that babble and chatter all day, these swallows sometimes breed in our nestboxes.

Silent winter’s end

Tree swallows dance through the sky

Spring’s symphony begins.

(A haiku)

Tracking Whimbrel

Whimbrel on the beach
Photo: Inge Curtis

An elegant shorebird with a lovely piping call of the wild. After they leave their breeding grounds in the tundra,  Whimbrels stop to feed on fiddler crabs in the mudflats of the Eastern Shore of Virginia. By October, they leave here for wintering grounds in the Caribbean basin and South America. The journey is thought to be along the Western Atlantic Flyway with other shorebirds, including Red Knot.

Dominion Energy is planning to build wind turbines about 23 nautical miles off our shores as a major contribution to reducing greenhouse gas emissions. To study the risks for migratory birds, the Nature Conservancy and the Center for Conservation Biology have attached GPS transmitters and altimeters to 15 whimbrels this year for mapping their route(s) on fall and spring migrations. Planners will be relieved if the birds avoid the wind farm and fly higher than the towering turbines.