GILLIAN FLACCUS Associated Press
PORTLAND, Ore. (AP) — A crowd of several hundred people gathered in the growing darkness outside Chapman Elementary School in Portland, Oregon, before the first Vaux's Swift darted into view high above.
Minutes later, thousands of the tiny birds were swooping and swirling like a cloud of pulsating black ink as they circled a tall brick chimney silhouetted by the fading light.
The humans below, watching from a patchwork of blankets and empty picnic baskets, cheered as the flock poured into the chimney all at once, like water spiraling down a drain.
The swifts' noisy migratory stopover each fall has made this chimney famous with bird lovers as far away as Europe and is a quirky Portland tradition so embraced by locals that the school keeps the diminutive Vaux's Swift as its mascot.
But in recent years, fewer of the beloved birds have shown up. The birds were already struggling because of the destruction of old-growth forests and now some scientists believe they are being further impacted by the destruction of old brick chimneys along their migratory path.
The birds can fly for about 100 miles at a time between stops as they travel from Canada to Mexico and back each year and roost in large numbers in tight, enclosed spaces because their body temperature drops at night.
But the decades-old smoke stacks they've adopted are getting torn down and capped off along the West Coast because of redevelopment, seismic concerns and an urban annoyance with swift poop and noisy flocks. When a chimney that's been a major roosting site disappears, no one is sure exactly where they go.