OBOL and Tweeters,
I have been looking into the vocalizations of the Western Flycatcher
complex for the past several years. Since I have some experience in
bioacoustics, but don't have a very good ear, I use spectrograms to compare
sounds. For now, I subjectively compare samples from the interior northwest
(Cascades to Montana, north to Alberta and e. BC, and s. to ... ?) to
standards from the four corners states (for COFL) and from the immediate
coast (for PSFL). I am going to have to do statistical analyses, but that
is in the future. My standards are at

http://www.appliedbioacoustics.com/research/wefl

That website presents samples from two important areas in Oregon. I just
back from a trip to e. WA, w. Idaho, and ne. OR. A few impressions, after
cursory spectrographic inspection of most samples:

Overall, the samples from w. Idaho and e. WA and ne OR are similar to those
from Lake and Deschutes Counties, OR, which are already on my website. (It
will take some time, probably in the fall, before I can get the current
round processed and up on the web.) In other words, they are intermediate,
but are perhaps more COFL-like than PSFL-like. It would take stat. analysis
to quantify where they are in the spectrum. Male position notes (MPN) all
tend toward COFL. Two or more gave clearly two-parted calls. The ones I
noticed in the field were the bird Charlie Wright reported at the first
creek ford in S. Frk. Coppei Creek, WA, and one along Old River Rd on the
west bank of the C. d'Alene north of Kingston, ID. Specifically, this bird
is about halfway between mile posts 3 and 4 where there are large
cottonwoods and a quiet channel by the road. When I looked at spectrograms,
though, many other birds had MPNs that were COFL in form, with perhaps a
less distinct break between the low and high part. You can see examples of
that on the web site. Others were typical of birds from the inland NW. None
of the MPNs were like those of coastal PSFL populations.

There is a distinctive song phrase 2 in the inland NW. It is intermediate
in form between the PSFL and COFL standards, although it occasionally turns
up in the core COFL area. All birds recorded on this trip had that
intermediate form of song phrase 2.

Song phrase 3 in this sample had an emphasized second note, which is COFL-like.

Pitch overall tended to be intermediate, which, along with the form of song
phrase 2, is the main reason for not calling these pure COFLs.

In the inland NW, song and the MPN do not covary exactly. In the region I
just explored, the MPN is more COFL-like than the song. You can't really
identify a bird as a COFL on the basis of MPN alone. Also, birders who are
relying on a low-amplitude break in the MPN can be led astray in a couple
of ways. (1) Some MPNs are perfect COFL except for not having an audible
silence in the middle. (2) Song phrase 2 of PSFL and the intermediate areas
does have a silent break. Birds often call mid-morning with Song Phrase 2
rather than MPN, or they may mix the two. In my experience, calling with
phrase 2 is at a faster pace than calling with MPN.

All of the above is based on subjective impressions, although I do estimate
frequencies by inspection of graph axes. I know I am going to have to do
discriminant function anaylsis before I publish this. That said, my current
opinion is that the entire interior NW is a hybrid zone. I think it is an
over-simplification to call all these birds PSFL. There is nothing wrong,
in my opinion, with calling them all WEFL. Please see the website for
amplification of these opinions.

I would like to thank the many people who gave me directions to WEFL sites,
especially, for this trip, Paul Sullivan, Charles Swift, Lisa Hardy, and
Charlie Wright.

Good birding and good empiding,

Arch McCallum
Eugene, OR