Date: 7/3/26 4:03 pm From: Steve Loitz via Tweeters <tweeters...> Subject: Re: [Tweeters] eastern WA birds moving west
A few thoughts:
1. Snoqualmie Pass and other WA Cascade passes are on a long-term warming trend due to climate change. The 2025-26 winter was the mildest winter we've seen in over a decade. IME, it is not unusual to see E WA and Central WA species spill over to the west side in mild winters. (FTR, I'm a frequent mountain traveler, on foot and ski.)
2. Yellow-breasted Chats and Lazuli Buntings could have moved north from the Willamette Valley, which has been part of their summer range for decades. I regularly saw both species when I lived in Eugene in the early 1980s. Both species have been summer residents of Basket Slough NWR for as long as I recall.
3. Range expansion across the warming passes may be a bi-directional phenomenon, possibly due to climate change. Some predominately W-of-crest species have recently become more common sights E of the crest -- e.g., Pacific Wren, Bushtit, Red-breasted Sapsucker, Western Flycatcher -- all of which were uncommon IDs in and around Eburg when we moved here in 2016, but are now relatively common IDs. Some might suggest that the Western Flycatchers in our area may be Cordillerans which moved W, but the WEFLs we hear in and around Eburg sound like the Pacific-slopes I heard during the 30 years I lived in and around Seattle, not the voicings of Cordillerans I've heard many times in the Kettle Range, Idaho Sawtooths, etc. Also, RBSA range is somewhat confusing due to (IME) increased RBSA x RNSA hybridization (again, possibly the result of climate change warming), althogh we have had numerous confirmed sightings of RBSAs in the past few winters that did not appear to be hybrids. Also note that RNSAs migrate S out of WA in winter.
