Both creeks I fished yesterday all head to the Arkansas. Cutthroat are hard to tell apart other than snake river cutts that have also been planted in the S. Platte. Rio grande Cutts are also relatively easy to distinguish from their cousins but are also geographically different.
There have been many cases out here where the CDOW has planted greenbacks, and not so pure Greenbacks, over other cutthroat Pops. The Cutts and brookies I got into came from Middle Beaver Creek in Pikes Peak National Forest. Can't get over the fact that these awesome wild fisheries are only 28 miles from my house.
I have a bead on a stream up by RMNP for supposed pure Greenbacks. I think that report will ahve to wait for warmer weather as it is above 11,500.
Have a Good 'Urn,