In the latter parts of December I began noticing a Dark-eyed Junco working my back yard feeders that had tidy white wing bars and all gray upperparts. Combined with my location in Colorado the signs seemed to point to a White-winged Junco, well within expected winter range for that subspecies and indeed far from the first of its kind in my yard. But after a few days of glimpsing the bird I finally studied it more carefully and began doubting my initial assumption. One thing that gave me fits about the bird was its seemingly magical ability to show and then lose its wing bars, only to again get them back upon further scrutiny. Was I jumping between different birds without realizing it, were my eye floaters really acting up, or was I just losing my mind? Also, the bird seemed a bit too dark and lacked the contrastingly darker lores that I ‘m accustomed to seeing in White-winged Junco. So when the opportunity presented itself I set up a photo blind near my brush pile and rigged up my scope for some digiscoping to see in close detail what was going on.
As it turned out, the bird’s left side had two crisp white wing bars (the upper bar distinctly shorter but there) while the right side only had a couple of weak white tips to the greater coverts. I now suspected that the bird was a Slate-colored Junco with wing bars, a variant illustrated and described by David Sibley in his eponymous Guide to Birds (have you pre-ordered your 2nd edition yet?) To confirm my hunch I emailed some of my friends who scrutinize juncos even harder than I do (Ted Floyd, Tony Leukering, and Steve Mlodinow) who all agreed with my assessment. Anyway, I really like birds like this with a unique trait that makes them stand out from the crowd, and even better when they cooperate for photos! I’ll leave you with a bit of video of the bird, again showing the differences on its left & right sides: