The sight is truly spectacular. Every September, an estimated 30,000 Vaux's swifts rise and swell from the chimney of the old Chapman Elementary School in Portland, Oregon.

Photo from colleenpatriciawilliams.com

Vaux's swifts are the smallest of the swift family and are native to the Pacific Northwest according to the website All About Birds:
http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Vauxs_Swift.html

A local filmmaker decided it was time to document the swifts' timely flights of fancy and joined the crowds near Chapman Elementary School last September to film the beautiful birds and also take soundbytes from the crowd:
http://www.oregonlive.com/living/oregonian/index.ssf?/base/living/121970672826730.xml&coll=7

His film, On the Wing will show in Portland in October and may be available for wider release at a later time.

Artist's rendition from davidcarmacklewis.com

Enjoy this video of the swifts entering the chimney. It's hard to get good shots of the beautiful old school and catch the birds on film: