Darrel, et al,
When I began birding in Oregon, the traditional place to look for Tricolored
Blackbirds was in the Klamath Falls area. One thing you didn't mention was
the presence of some birds at the St. John's landfill back in those early
years.
Tricolored Blackbirds are indeed colonial nesters. They are also subject to
persecution by Redwings in certain circumstances, which prompts them to move
periodically. The scenario you propose could have happened.
I also can offer this about detection of the birds: I was watching the
colony in the Painted Hills. They were up on the cattails calling in their
raucous style. Then something triggered a "get down" command, and the
entire flock disappeared down into the cattails in an instant. No birds
could be seen. Even if the birds are present, one sometimes had to hunt for
them.
Contrary to published reports in Oregon Birds, I was the one who found the
birds near Hermiston on April 21, 1989. In connection with that sighting, I
was contacted by researchers in California who were writing a paper on the
decline of the species in that state. I believe that result was published.
Here are the years I have recorded for my first sighting of Tricolored
Blackbirds in eastern Oregon counties:
1985 Klamath
1989 Umatilla
1992 Wasco
1992 Wheeler
1995 Hood River
1995 Crook
2002 Morrow
2004 Jefferson
2005 Gilliam
2010 Sherman
Here are the years of my first sighting of Tricolored Blackbirds in western
Oregon counties. The western Oregon sightings were typically isolated
individuals
1991 Marion
1992 Multnomah
2000 Polk
2001 Washington
2005 Lane
2014 Yamhill
I would also note that the species has expanded into central Washington
State in recent years and is now breeding there as well.
Good birding,
Paul Sullivan
--------------------------------------------
Subject: on Tricolored Blackbirds
Date: Mon Mar 21 2016 10:08 am
From: 5hats AT peak.org
Paul Sullivan's recent discovery of Tricolored Blackbirds in Gilliam County
prompted this post.
Prior to about 1980 the only known breeding locations for the species were
located in southern Oregon, primarily in Klamath and Jackson Counties. Then
sometimes around the early 1980's ( I don't have the exact date) a small
colony of them was discovered near Camp Hancock in southeastern Wasco
County. This spot is approximately one hundred seventy miles north of any
breeding location known to exist at that time. Within a very few subsequent
years other colonies were located near Hermiston in Umatilla County,
Prineville in Crook County, and at the Painted Hills Unit of the John Day
Fossil Beds near Mitchell, Wheeler County. There were also reports of a few
birds near Portland, Multnomah County, as well as in other scattered
locations in the north-central part of the state, where they seem now to
have become regular. The species has been recorded in Wasco, Sherman,
Gilliam, Morrow, Umatilla, Wheeler, and Crook Counties, with breeding
reported in most of them.
It is speculation on my part, but I have long suspected that this spread of
the species into north-central Oregon was not the result of a range
expansion from southern Oregon, but rather a dispersal of birds from a
previously unknown breeding location closer to the area, and there is at
least some data to support the hypothesis. About twenty miles northeast of
Madras, very near the now defunct town of Willowdale, there used to be a
large cattail marsh on the west side of US highway 97. This particular marsh
was a couple of miles long, probably at least a mile wide, and completely
inaccessible. The cattails which grew in the marsh were higher than a man's
head, and there were no elevated places along the highway from which a
person could see out over the marsh. It is not at all unreasonable to think
that an inaccessible marsh of that size could have hosted a colony of
Tricolored Blackbirds without anyone ever detecting their presence. I
believe it was in 1979 that the marsh was drained and converted to cropland.
My records show that on June 9,1980 at Willowdale I saw a Sora at dawn in
what had formerly been a cattail marsh. It was the year after that marsh was
drained that the Tricolored Blackbirds were reported at Camp Hancock, which
is only a few miles to the northeast, and subsequently began to be reported
in other spots in the north-central portion of the state.
If Tricolored Blackbirds did once have a colony at Willowdale (and it cannot
be proved they did), it is interesting for several reasons. (1) It means
that the species had a breeding location in Oregon, unknown to birders,
nearly two hundred miles north of any previously known breeding location.
(2) It explains the sudden and surprising spread of the species into the
north-central portion of the state. (3) it suggests that the species is
perhaps more adaptable than previously thought. Tricolored Blackbird is
known to be a colonial nester, most colonies being made up of numerous pairs
or females and polygamous males. Most of the colonies which now exist in
north-central Oregon are relatively small. I never counted birds, but the
largest colony I have observed was the one which nested for a while between
Prineville and O'Brien. It had maybe a couple of hundred birds. The one I
saw near Hermiston had perhaps half that many. The one at the Painted Hills
Unit of the John Day Fossil beds I do not think had over twenty birds total.
One of the thing which makes tracking this species a bit difficult is that
their breeding colonies in the north-central part of the state seem to shift
locations from time to time. There are undoubtedly people who know far more
about the numbers of birds and the locations in which they breed than I do.
I am only piecing together what little data I have from occasional trips to
the area, and none of it has hard documentation in terms of numbers. However
the continuing reports of this species in that section of the state suggests
it has successfully colonized a new area, and is continuing to expand its
range within that area. I present this post to give this apparent range
expansion a bit of historical perspective.
I might also add that Paul's recent discovery of the species in Gilliam is
not unprecedented. Once previously he found a small breeding colony of them
along Rock Creek near the bottom of Wolf Hollow Road south of Olex. I have
looked there several times since and seen only Red-winged Blackbirds.
I would encourage those who know more about the presence and spread of this
species into north-central Oregon to contribute to this thread.
Darrel
POST: Send your post to obol@xxxxxxxxxxxxx
JOIN OR QUIT: //www.freelists.org/list/obol
OBOL archives: www.freelists.org/archive/obol
Contact moderator: obol-moderators@xxxxxxxxxxxxx
