Mountain Chickadee

The obvious difference between the Mountain Chickadee and the Black-capped Chickadee is that the Mt bird has white racing stripes in its cap, or white eyebrows, if you will. There are other more subtle differences, such as a thinner bill and shorter tail, but I rarely see them side by side. I just learned that that the eyebrow feathers are black with white tips, and that the white wears off during the summer as the birds enter and exit their nest holes, but then is refreshed after a late summer molt. This stripe looks pretty fresh, so I guess the late summer molt has happened.