Dusky phase Blue Grouse. Note that the Dusky phase has a mauve-colored cheek sac, and that the tail is a solid dark grey with a very thin silver tip to the feathers. The Sooty phase has a yellow cheek sac, and the Sooty's tail feathers sport a very broad silvery band across the tip.
Sooty phase Blue Grouse. The yellow cheek sac and the broad silver band across the tail tip distinguished the Sooty phase from the Dusky phase.
Ruffed Grouse Bonasa umbellus
