The juncos, also called snowbirds, know how to navigate winter weather. Perching on an icy branch is probably not a good idea so they hung out on the ground picking up peanut pieces.
I did have fun watching a squirrel try to dash off when I opened the sliding glass door. He skittered up the trunk of the dogwood tree without too much trouble, but trying to leap from icy branch to branch was beyond his capabilities. He slithered back down to ground level and found a more down-to-earth escape route.