>More interesting was the comment about the song. I haven't been able to
>distinguish Myrtle from Audubon's by song (although it is easy by
>chip-note), and I didn't think their songs were supposed to be
>different. Does anyone else have contrary information? How did the
>songs differ, Clark? Certainly birds of different populations may have
>different songs, but I had understood that the variation in Myrtle and
>Audubon's songs, whatever it was, caused them to overlap substantially.

It seems to me that the typical song of our breeding Audubon's Warblers
is recognizably different from the Myrtle Warbler song I knew growing up
in the midwest. However, though I have put some effort into trying, I
have not been successful in differentiating migrant Myrtles from Audubons
here in Oregon. The midwestern song is a soft, sibilant, warble, with a
falling inflection, without much of a pattern to hang onto. The western
birds, both Myrtle and Audubon's, seem to have a slightly deeper, louder,
more musical warble, that can almost be described as very a slow trill.
On occasion, I have heard birds here that sounded like midwestern
Myrtles, and have found them usually, but not always, to belong to Myrtle
Warblers. I suspect there is a great deal of variation in the songs of
both species.

BTW, good numbers of both forms were singing on Sauvie Island this past
Saturday. Audubon's outnumbered Myrtles about 5:1.

Skip

--
Skip_Russell at intersolv.com
Aloha, Oregon