Each spring in Yellowstone, the male (cock) Dusky grouse(Dendragapus obscurus) put on a wonderful display to attract a mate (hens). Their eyebrows turn a bright yellow or orange and they strut with tails flared and special air sacks exposed and pumping. Air pumping through the sacks produces a very soft drumming sound. The softness of the sound makes the cocks difficult to locate. They are often closer to you than the sound would imply. When the cocks are not displaying, the tail is down...
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Each spring in Yellowstone, the male (cock) Dusky grouse(Dendragapus obscurus) put on a wonderful display to attract a mate (hens). Their eyebrows turn a bright yellow or orange and they strut with tails flared and special air sacks exposed and pumping. Air pumping through the sacks produces a very soft drumming sound. The softness of the sound makes the cocks difficult to locate. They are often closer to you than the sound would imply. When the cocks are not displaying, the tail is down and sacks closed. Petrified Tree, Yellowstone.
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