Mt. Evans Wilderness area, on the Rest House Trail four miles in from the Echo Lake trailhead. I found one adult male White Winged Crossbill atop a tall Lodgepole, singing. I heard others nearby, but I didn't see them. They moved on quickly, as crossbills do. I saw Red Crossbills in the area as well. This was my first White Winged, but as I saw it in very good light (I was even able to discern the crossed bill) I can be confident in the identification.