For some years, a Ruffed Grouse has been a regular visitor to my yard. Then all visits stopped. Subsequently, I learned that a local dog had been its executioner.
Two days ago, I heard the wing beats of a flushed grouse in my yard. Today, I saw it. I think it is female.
From this view, I would not be able to tell whether this Ruffed Grouse beside my house was male or female. 
However, an indicator of the sex is revealed by a spread tail, such as seen in this shot from the side back. The evidence is in the tail’s terminal black band. If the band is continuous across the full width of the tail, then the bird is male. If there is a break in the middle as seen here (lower right of picture), the bird is probably a female.
Despite the loss of the previous grouse, the arrival of a new female just might bring chicks.
Could not that break in the tail band be a molt limit? I am looking at Peter Pyle’s Identification Guide to North American Birds Vol II and find a different differentiation between male and female.
Meanwhile, I hope it is a female too. The invasion of Wild turkeys in the last decade (up to 150 at a time at our place) has had me worried about the small Ruff grouse population on our property. Last spring a trio of Ruffed grouse walked through so I hope the niches both species occupy do not overlap.
Just lovely photographs! Another keeper,
Tina
Tina, I don’t have Pyle. But, birding (and hunting) sources I checked suggest that if you cannot measure the length of the central tail feathers (the ideal determinant), seeing a break in the black band on the tail is a strong indicator of the bird being female. However, I am fishing; maybe others have some insights on this. As to Wild Turkeys, we certainly have them (migrated here from Washington and Idaho), but I see a grouse more often than a turkey in my yard.