99. Greater Prairie-Chicken-Vyn-070414-0071.tif
Aggressive encounter between two male Greater Prairie-Chickens (Tympanachus cupido) on a lek. During aggressive encounters males lower their pinnae feathers, deflate their air sacs, leap into the air, and strike their opponent with feet, wings, and/or beak. Ft. Pierre National Grassland, South Dakota. April.