eWestern Birds
The Quarterly Journal of Western Field Ornithologists
Seasonal Population Fluctuation of White-throated Swifts at Roost Sites in Southern California
Thomas P. Ryan and Charles T. Collins
ABSTRACT: In southern California, White-throated Swift (Aeronautes saxatalis) roosts contain many more individuals during the winter months than during the breeding season. Dates of the high and low counts at these roosts fluctuate from site to site and from year to year. Evidence suggests that some individuals remain and nest at or near the roost; whether others migrate north to breeding areas remains unknown.
Download—Seasonal Population Fluctuation of White-throated Swifts at Roost Sites in Southern California