Many accounts are incomplete although new information is being added continuously.
Errors do occur.
Users are cautioned to refer back to the original cited source to assess completeness and correctness before using the information. Web updates are intermittent, not continuous, therefore some dynamic information such as legal status may not be absolutely current. The two species are widely sympatric, but clarkii is rare among northern populations, becoming equally common among southern ones. Supplement to the Auk. 99, No. 3, July 1982.