As mentioned under pic 1959 the species also gather in green fields.
1956 (4 photos) 2010-06-20 Presa El Salvador, El Llano, Aguascalientes (Agu), Mexico
Adult with worn feathers and reddish tips to various shoulder feathers and coverts. The wing movement probably is an intend to protect its offspring. Don't remember it well, but have registered a juvenile bird from the same place, so it sounds likely.