Townsend's Warbler during fall migration. This western Wood-Warbler breeds up into southeast Alaska and also east central AK, south Yukon, north B.C. including Queen Charlotte Island and Vancouver, sw Alberta, west Washington, Oregon (esp. east-side of the Cascade's, central Idaho, and west Montana. Winters 2 separate areas: coastal population winters along coastal CA and down into Baja California and the largest numbers are found in central CA. The other group winters in the mountains of Mexico, south to Nicaragua and is a rare but regular visitor to Costa Rica.