When I first joined IBLE (lo, these many years ago), I went birding with RL and he directed me to a small neighborhood out Warm Springs, near where Idaho 21 now crosses the Boise River. We went there to see the Lesser Goldfinches that--apparently-- could be found nowhere else in the Treasure Valley.

Within a few years, I started seeing Lesser Goldfinches at my feeders in the North End. Now, I see and hear them all along the Boise River, at least to Eagle Road. (Going to Eagle Road is a LONG bike ride for me, and I have rarely ventured beyond it.)

Long story short—I think they have been expanding their range in the valley for some time. If I were you I would greet them warmly, maybe put out an extra sock feeder (they love nyger thistle), and sit back and enjoy. Their year round yellow is a delight on a dreary winter day.

Tom McCabe, Boise