EPOW - Ecology Picture of the Week

colony of Vaux's Swifts (Chaetura vauxi), Portland, Oregon

Explanation:   It is summer in North America, a time when forests and chimneys play host to several species of swifts.  But there are few urban locations, such as this school in Portland, Oregon, where one can view such an immense colony as this swarm of swifts.  

They are Vaux's Swifts ... by the tens of thousands.  In a previous EPOW, we explored their calls and songs.  But here is an immense summer colony that nightly swirls and swarms in fantastic numbers before plummeting into this chimney to roost for the night. 

We are at Chapman Elementary School in Portland, which has become well known for this amazing nightly sight.   Portland Audubon Society has donated funds to help make the heating furnace usable by both birds and the school.  More than that, the school adopted the swift as a mascot and as part of its curriculum.  

A patient Cooper's Hawk waits on the lip of the 
chimney for the right moment to strike!

Vaux's Swifts usually inhabit tall hollow trees and snags in old forests, but some colonies have taken to the urban and suburban scene and, like Chimney Swifts of eastern North America, use chimneys instead for nest and roost sites.  We can help conservation of swifts, nighthawks, and other species, by providing such nest and roost sites -- which seems fair, given that we have often taken away their forest habitats.  

Click on the following buttons to view short videos of this swarm funneling down into the chimney at dusk:

 
Video 1.  Approaching dusk, the swifts gather near the chimney opening.  Sounds of the crowd assembled to watch can be heard. (843KB mpg, © Bruce G. Marcot)

Video 2. In the gathering dark, a final tornado of swifts amasses and vortexes down into the chimney (1.35MB mpg, © Bruce G. Marcot)

Information:  
   Bull, E. L., and R. C. Beckwith. 1993. Diet and foraging behavior of Vaux's swifts in northeastern Oregon. Condor 95:1016-1023.
    Bull, E. L., and H. D. Cooper. 1991. Vaux's swift nests in hollow trees. Western Birds 22:85-91.
    Bull, E. L., and J. E. Hohmann. 1993. The association between Vaux's swifts and old growth forests in northeastern Oregon. Western Birds 24:38-42.

Also see this "Swallows-Martins-Swifts-Worldwide" Yahoo discussion group.