Animalia, Aves, Chordata, Hirundinidae, May, North America, Passeriformes, T. bicolor, Tachycineta, Tachycineta bicolor, US, USA, Wisconsin, adult bird, bird, close, close to the camera, close up, close-up, closeup, eating gravel, female, female tree swallow, gizzard, gravel, natural, nature, near, north american, northern Wisconsin, northwoods, picking gravel, picking up gravel, song bird, songbird, spring, spring time, springtime, swallow, tree swallow, wild, wildlife