if canary grass has an impact in respect to wetland/migratory ducks
The wetland experts heavily frown on reed canary grass in wetlands, especially in Clay Co. As a side note, horses love to eat reed canary grass early in the year, it is one of the first things to green up and a few horses will do a decent job of keeping the reed carnary grass under control without chemically spraying for it in a wetland. It was one of the things my little brother and his wife "taught" the wetland experts in Clay Co. a few years ago.
As a pheasant hunter though I prefered having the canary grass in his wetland, it was the most likely type of vegetation that my pointers would lock a pheasant down in. With the canary grass gone the "ditch parrots" seem to run like crazy now and are much harder for my dogs to get those "ditch parrots" locked down.