I agree with Michael that the swifts were probably mating (=copulating).
I've always been amused by our use of "mating" for copulating in other
animals, although I don't think we use that verb in that context for
ourselves. I guess it was generated in the farmyard when the kiddies asked
"what are those cows doing?" At least that's better than "fighting," which
I've heard people say to their offspring while viewing some pets in the
act. Wonder how many sexual hangups that caused?

Probably all swifts copulate in flight, the only birds to do so. At
Frenchman Coulee in Grant Co., WA, you can watch White-throated Swifts
performing this amazing feat. Interestingly, I've never seen Vaux's Swifts
copulating. Has anyone else out there?

Wow, while typing this I caught a quick movement and looked up to see a
hummingbird rocketing away from my third-floor window. First for my office
list.

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416