Vaux’s Swifts, small insect-eating birds sometimes described as “cigars with wings”, migrate south en-mass each year, roosting as they travel in hollowed trees and industrial chimneys.

Since the mid 1990s, the Swifts have roosted each September in the chimney of Chapman School in NW Portland, Oregon. Each year hundreds of onlookers gather on the lawn of Chapman school, from about an hour before sunset to about a half hour after, to watch the Swifts gather, organize, perform aerial maneuvers, and finally funnel in a black fluttering cloud into the chimney to roost.