Hi -
This is an interesting idea. In the last few years I have located Tricolored
Blackbird colonies several times in the Klamath Basin, some previously known,
some apparently not. The locations have mostly been dense stands of stinging
nettles on canal banks in agricultural lands, and the birds have been foraging
out in the cultivated fields. Locations have included Tule Lake, where the Auto
Tour route follows the levee on the south side of Sump 1A. The levee is
separated from agricultural fields to the south by a canal, and the nettle
stands are on its banks. One year (2013?) a colony formed on the south end of
the tour route in Lower Klamath NWR. Another location is along Algoma Road, SE
of Hagelstein Park, off the east side of Upper Klamath Lake. I have also seen a
few birds in Upper Klamath Marsh along Military Trail, and I suspect there was
a colony somewhere out in that more natural habitat.
Wayne
From: "5hats@xxxxxxxx" <5hats@xxxxxxxx>
To: "obol" <obol@xxxxxxxxxxxxx>, "vanwing" <vanwing@xxxxxxxxxxxx>
Sent: Monday, March 21, 2016 8:07:46 AM
Subject: [obol] on Tricolored Blackbirds
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
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