Clark Blake wrote: "I had four bright male "Myrtle" warblers in Bellingham
this morning. They were singing quite a different song than the more common
"Audubons". These are the first Myrtles i have seen this year. I know that
they winter farther south but does anyone know if they are common during
Spring migration in western Washington?"

Yes, "Myrtle" Yellow-rumped Warblers are common during spring migration in
western WA (also eastern WA, but less common); sometimes flocks I see
contain about = numbers of Myrtle and Audubon's, sometimes much more of one
than the other. The Alaska-breeding Dendroica coronata hooveri (a "myrtle"
warbler, like D. c. coronata) winters in large numbers on the Pacific coast
from sw. WA to CA.
Observers should continue to keep their Yellow-rumped records divided into
Myrtle and Audubon's whenever they can, to avoid the downside of losing
information about lumped populations.

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.

Dennis Paulson
Slater Museum of Natural History
University of Puget Sound
Tacoma, WA 98416
206-756-3798
dpaulson at ups.edu