While the Columbia Gorge is the easiest route and does likely account for some of the Anna?s records (especially records in places like Walla Walla County, Vantage etc..), I?m not sure the data support this route for some east slope Cascades sightings. I?ll take Yakima County for example. Most of the first records for Anna?s each year occur in the east slopes, not in the Yakima Valley or along US-97 (the route that Western Scrub-Jays and Lesser Goldfinches have used for dispersal). Numbers of Anna?s increase as we go into September for Yakima Valley, while Cascade sightings are more common starting in June. Similar with Kittitas County in that Cle Elum and upper county areas often have records before Ellensburg or areas closer to the Columbia River. It seems unlikely that these birds are passing through well birded population areas and going undetected, only to show up in higher elevations first.

Scott Downes
downess at charter.net
Yakima WA