Subject: [Tweeters] Question: "mixed" empid migration?
Date: Sep 8 12:38:11 2009
From: Paul Hicks - phicks at accessgrace.org


Tweets,
When it comes to empidonax flycatchers, I generally lack the confidence to
make a definitive ID without vocal verification. However, I am all but
certain that the last two weekends I observed (and heard) Pacific-slope and
Hammond's Flycatchers together. So my question: Do these two empids
typically migrate or associate together in the fall?
Last week I had a point-blank view of a gorgeous, bright/fresh empid that I
concluded was Pacific-slope based mainly on the larger bill. Shortly after
it disappeared I heard a Hammond's distinct hard "hic-up" type song/call
from off in the same general direction. Then twice more. I thought, "Well, I
got that one wrong. (No big surprise)." While trying to track this bird(s)
down a Pacific-slope's dissyllabic song/call sounded from the vicinity of
the first sighting. The two could not have been much more than 100 feet
apart. They may have been loosely associating with a mixed chickadee-warbler
flock.
Yesterday a Pacific-slope materialized out of the brush at a wooded edge
showing a large bill and a breast-band looking demarcation between the
higher (dingier) and lower (brighter) underparts--almost like a long, broad
"bib" (as opposed to a "vest"). After some time a second empid appeared with
a detectibly-but-not-obviously smaller bill and an indistinct "vest" pattern
below. But the differences were not so pronounced that I could be certain.
The two interacted a bit a few times over several minutes, even sharing the
same branch briefly at one point. So I'm thinking, "Confusion, here we go
again." Soon I heard a Hammond's hic-up song/call, once, so I was both
relieved and perplexed. What about the first bird that I had dubbed
Pac-slope? That bird was not cooperating to allow another good view. But
from out of the din of the mixed chickadee-warbler flock I had worked up I
realized I was also hearing the repeated, faint locator call of a
Pacific-slope. Several minutes later it emitted its dissyllabic song/call
(once) --which, honestly, struck me more like a Cordilleran but given the
time of year ("off season" and possibility of young birds) and my lack of
experience with this species I'm not putting much stock in that impression.
Have other Tweets observed "mixed" empid movements during fall migration?
Good birding!
-- Paul Hicks / Tenino, s. Thurston Co / phicks AT accessgrace.org