Stock photography, photos: Ornithologist monitoring growth of Stock photos of Ornithologist monitoring growth of young tree swallow. Wings painted for identification purposes Photograph: © John T. Fowler Click for a larger image and more information Keywords associated with this stock photo: Ornithologist, monitoring, growth, young tree swallow. Wings, painted, identification, purposes, migratory, songbird, song bird, vertical, science, scientific, research study, experiment, pesticide, Iridoprocne, bicolor