>Situations where controversy reigns involve identifying species by song. I
>know birders with "decades of field experience" who can't tell the
>difference between the songs of Yellow Warblers and Wilson's Warblers, but
>are doing Roadside Breeding Bird Surveys. Some of these same people also
>identify birds slightly-out-of-range or -season by voice alone.
>
>--Jerry Tangren
><tangren at wsu.edu>

I too know of numerous cases in which BBSers don't know the vocalizations
of all the species on their routes. One study of Breeding Bird Survey data
showed that basically every time the observer changed, the census changed.
The only thing one can hope is that all of this inconsistency cancels
itself out, which is not as absurd as it sounds.

But I don't know how to avoid the possibility of error that Jerry brings up
in his last sentence. Very experienced birders do the same things, as
indicated by the number of Willow Flycatchers that have been called Alder
Flycatchers in the Northwest by rare-bird seekers. Somehow we keep coming
back to the basic problem: people are only human.

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416