These photos were taken at a Greater Sage Grouse, (Centrocercus urophasianus), mating lek in Colorado.  The males gather before sunrise to display, dance and call to entice the females to chose them for mating. The male inflates special air sacks on his chest and uses them to make a deep bonk-a-bonk-bonk sound. Each male tries to stake out and defend a territory. The females choose only a few of the males for the mating, which lasts only a few seconds.

There is also stock film footage of the endangered Gunnison Sage Grouse.