Hello, Drew, and Tweeters,

Cassin's Vireos are hit and miss as breeders in Clallam County, but
they apparently nest somewhere along the Dungeness River riparian
forest most years. We have had them singing in Railroad Bridge Park
just west of Sequim since early June this year - they were still
singing away last Wednesday. Whether they have a post-breeding
northward dispersal is a good question, but at least some are
apparently breeding here. I've heard them other years singing in mid-
late spring at other locations on the north Olympic Peninsula, such
as along Louella Road east of Sequim and at the Elwha River near Lake
Aldwell, but I don't know if they nested. I'd bet that they also
nest along some of the lowland riparian forests to the west, like
along the Twin, Lyre, Pysht, or Hoko Rivers, but I don't know for sure.

Curiously, Red-eyed Vireos sang loud and clear in RR Bridge Park
during the 2003 - 2005 breeding seasons. They apparently nested, as
we saw REVI adults carrying caterpillars through in the cottonwoods.
But in 2006 there was almost a complete reversal, with Cassin's
singing in the park and no Red-eyeds in 2006 nor 2007. Could the
Cassin's have moved in and excluded the Red-eyeds?

We also have an interesting spring passage of Cassin's, with singing
males heard along the Dungeness and reported in Port Angeles nearly
every year in a window of time usually between April 8 -15, but they
don't seem to stick around. We then get the usual breeders singing
here in late May or early June. Where are those early CAVI heading?
It seems like I get very few reports of CAVI during fall migration,
so after breeding they just fade away, or maybe they feed so high in
the trees and don't make any sounds that we just don't see them. But
mostly I hear about CAVI from my regular reporters who know their
song, such as Judy Mullally who lives in east Port Angeles, and
Sheila Joyce, who lives along the Dungeness River.

Last Wednesday's bird walk in RR Bridge Park (every Wed at 8:30 a.m.)
was a three vireo day, with Hutton's, Warbling, and Cassin's all
singing away.

So you ask a good question, for which we only know a little. And
thanks for all your other bird sightings!

Bob Boekelheide
Dungeness River Audubon Center
Sequim



From: Wheelan Drew <amazilia55 at yahoo.com>
Date: July 8, 2007 9:49:17 AM PDT
To: tweeters at u.washington.edu
Subject: [Tweeters] Cassin's Vireo Status on Peninsula?


Hey All, I keep forgetting to ask this. The other
day as I was getting in my car to go to work and heard
what sounded like a Cassin's Vireo in my yard. I know
that Hutton's can be pretty darn variable, but
"generally" it seeems that they are mostly repeating
the same "phrase", and not doing the question/answer
thing. Also, I know the Hutton's in my yard pretty
well, and I haven't ever heard them from where this
one was singing. How uncommon are they here in Port
Angeles, is there maybe a post bredding northward
dispersal? Any info on this would be appreciated,
Drew Wheelan
Port Angeles

Andrew S. Wheelan
www.hermaninstitute.org
The Herman Institute of Biological Studies




-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman1.u.washington.edu/pipermail/tweeters/attachments/20070708/e0badde7/attachment.htm