a tree swallow pokes its head out of a wooden nest box in wissahickon valley park, philadelphia, pennsylvania, usa

american animal avian beak bicolor bill bird bird box portrait watching birdhouse birding blue bright brooding closeup cute fauna feather head house looking meadow natural nature nest nest nesting ornithology outdoors park peek peeking poke pretty sitting small swallow tachycineta tachycineta tree tree usa white wild wildlife wissahickon wissahickon valley wooden