Vaux's Swifts entering chimney

At the same time (literally) that the Barn Swallows are going to roost in the cornfields, the Vaux's Swifts here in western Oregon are going to roost in chimneys all over the Willamette Valley. This evening about 300 to 500 went into a chimney of house on my street, as they do every evening for several weeks each September.