I forget the exact timing but I saw a butterly (moth?) in Rock Creek Park one warm day back in February while there was still a thin layer of snow on the ground.
If it was dark with a yellow border flying kind of high through the trees, then it was a Mourning Cloak. They often wake up and take their chances on a warm day in Jan-Feb.
More or less my eye level when spotted. Maybe dark with a yellow border.