Summer is advancing toward the time when this fledgling Yellow-rumped Warbler (Dendroica coronata) must make its first long migration. The tan and yellowish feathers coming in on its throat, breast and the sides of its belly are just the beginning of a new set of adult feathers that are replacing the down of a nestling with flight feathers enabling flight and contour feathers that will stream line its flight.

Location: Glacier National Park, MT