Dusky Grouse female

This photo was taken on 27 August 2014, the second day of a three-day trip down south, to Waterton Lakes National Park with friends, Cathy and Terry. We were driving along the Red Rock Parkway when we noticed a bird crossing the road way in the distance. We weren't sure what kind of Grouse it was, but, when we got closer, I got out of the car and went to see if I could get a better view of it. To my surprise, there were also several young ones hidden in the grasses. Amazingly, they didn't hurry off, out of sight, but instead stayed where they were until my friends came to look. Then another car slowed down and stopped to see what we were looking at, shortly followed by a small van that carried quite a few people. Maybe everyone had perhaps been expecting to see a Bear, ha. After a while, yet another vehicle stopped and out got a Park Ranger. I suspect he thought we were a crowd of foolish people who had got out of their cars to get closer to a Bear. When he realized that all we were watching was a family of Grouse, a big grin appeared on his face. Makes me laugh every time I picture his expression : )

I have searched and searched for the ID of this Grouse, but photos and IDs left me more confused than ever! The closest I have come to is a Dusky Grouse female, but if anyone is able to either confirm or correct, it would be so much appreciated.

The Checklist of Birds in Waterton Lakes National Park (a pdf file) says that Dusky Grouse are uncommon in the park.