Tim et al.,
The interesting thing about this upslope expansion is that it took roughly
20-25 years (from the point that Anna's became commonplace in the Willamette
Valley) for it to happen. For those who weren't birding in Oregon back in the
1970's, you'll probably be surprised to learn that until about 1975 or so,
Anna's Hummingbird was a rare bird in the Willamette Valley. I actually had to
make a concerted effort and go to the Portland home of a birding friend of mine
to get my state Anna's on 31 December 1977. It was my 300th Oregon bird at the
time.
The initial expansion into Oregon seems to have been driven by a northerly fall
dispersal, as Anna's would often show up in October/November at a feeder that
someone forgot to take down at the end of the Rufous Hummingbird season (early
September). These feeders were almost always at or near the valley floor in
residential areas. I wonder if the driver in all of the expansion of Anna's is
critical population mass. Anna's are now abundant throughout the year around
every Willamette Valley town that I have spent any time in. Perhaps the
population density has reached a point where they have to push out at the edges
of what has historically (short-term) their range in the lowlands. This range
expansion is ongoing and now includes parts of Oregon that are east of the
Cascades. I don't have a good feel for Anna's status in Klamath Falls,
Bend/Redmond/Madras or other points farther east, but they are certainly there.
Perhaps Tom Crabtree, Judy Meredith or others can report on the status there.
Dave IronsPortland, OR
From: tjanzen@xxxxxxxxxxx
To: llsdirons@xxxxxxx; watice@xxxxxxx
CC: obol@xxxxxxxxxxxxx
Subject: RE: [obol] Re: Another question on range expansion
Date: Thu, 26 Nov 2015 23:35:16 -0800
Dear Dave and Bill,I agree with you about the upslope movement of Anna's
Hummingbird. Prior to about 2000 I could not find them in the Happy Valley
area where I live. If I wanted to see them in the Portland metro area in
Clackamas County I had to search for them along the Willamette River or in
appropriate habitat on the valley floor in the SW part of the county. However,
about 2000 Anna's Hummingbirds began appearing at my hummingbird feeders on Mt.
Scott where I live at about the 750 foot elevation level. They have breed near
my house consistently since then. They can be found with regularity elsewhere
in the vicinity on various hills as well. I don't know how far upslope in the
Cascades in Clackamas County that Anna's Hummingbirds breed, but I wouldn't be
surprised if they breed in the Sandy area or further east in the Cascade
foothills.Sincerely,Tim Janzen From: obol-bounce@xxxxxxxxxxxxx
[mailto:obol-bounce@xxxxxxxxxxxxx] On Behalf Of David Irons
Sent: Thursday, November 26, 2015 8:46 PM
To: watice@xxxxxxx
Cc: OBOL
Subject: [obol] Re: Another question on range expansion Bill, You raise an
interesting question about Anna's. Their range extends way to north, with the
Victoria, BC CBC now recording upwards of 500. The real interesting thing is
the upslope expansion that you allude to. For the most part this seems to be a
comparatively recent development. Prior to the last few years, Anna's on the
west side of the Cascades seemed to be mostly restricted to the valley floor,
not often being found very far upslope. Over the last couple years I have been
noticing Anna's at upslope sites in the Cascades and the Coast Range. Of course
my observations are colloquial and lacking rigorous protocols, but I don't feel
like I was just missing birds upslope in the past. Dave IronsPortland, Oregon
Sent from my iPhone
On Nov 26, 2015, at 9:56 AM, BILL ROSIE <watice@xxxxxxx> wrote:Since Tim R
brought up the question on breeding records of Kite and Red-shouldered Hawk in
the Willamette Valley, the subject naturally leads to the idea of range
expansion. In the last 20 years or so, we have watched Red-shouldered Hawks,
Black Pheobes and possibly Kites extend their breeding range. This leads me to
ask the question about Anna's Hummingbirds – I seem to get the idea that their
range has stretched as well. I live in Falls City, and up until maybe 5-6 years
ago, I had 2 records of Anna's at my place, here at the base of the coast
range. Now they are year round residents, although my feeders may keep them
here. Roy Gerig and I saw one once near Sugarloaf Mountain, half way to the
coast. I'd like to know what others think.
