We had lots of opportunities to photograph tree swallows, mountain bluebirds, western meadowlarks, and red winged black birds on the barbed wire and posts along the airport road in Custer State Park. There were bluebird nesting boxes affixed to the posts, some inhabited by bluebirds, others by tree swallows. The tree swallows were most active around the nest boxes while we were there. The male perches nearby, occasionally calling to his mate. The female checks out the nesting box.