Thanks to Eric's encouraging posting yesterday (and because neither I nor any of my uncles had seen it), I finally made the trek to Welchester Tree Grant Park in Jefferson County this morning. The Blue-winged Warbler was vocalizing constantly in the usual location at the east end, and was seen and photographed by several birders. The bird was still active until at least late morning (10:30 a.m.).
I was also delighted to still find this bird present after so long.
Kevin Keirn
Fort Collins, CO