Comments: Cottus bairdii as it has been used in the broad sense is a multi-species conglomerate; taxonomic subdivision of this assemblage is currently underway (D. Neely, pers. comm., 2000).
Morphologically distinct populations of C. confusus and C. bairdii, with some intermediate specimens, occur near the western border of the U.S. and Canada; thorough study of species limits is needed (Peden et al. 1989).
Markle and Hill (2000) recognized populations of the C. bairdii complex in Oregon as two species, C. bendirei and C. hubbsi, but the taxonomic and geographic scope of these taxa needs further study.
Formerly included in the order Perciformes; the 1991 AFS checklist (Robins et al. 1991) followed Nelson (1984) in recognizing the order Scorpaeniformes as distinct from the Perciformes.