Hi All,
Just to flog this subject a bit more, what about Scrub-jays?
From natives of the northwest, I've heard that they have only been here since
the eighties some time. I spent years working on passerine nest monitoring
projects, and they are a common cause of nest failure. Robins are very tight
sitters and something as small as a Scrub-jay might not cause a Robin to
immediately give up a nest, but Scrub-jays are very persistent predators.
The absence of Robins is probably the result of a combination of factors,
including local reproductive failure. A lack of birds immigrating to vacant
territory is also part of the picture.
Jim
On Friday, October 1, 2021, 03:07:09 AM PDT, Jeff Gilligan
<jeffgilligan10@xxxxxxxxx> wrote:
Lori
When there were hordes of crows, did they occur commonly during nesting season?
I ask, because roosts are typical in winter, or at least out of nesting season.
Regarding Lars’ comment about Steller’s Jays, only this summer has there been a
nesting pair in the blocks near my house. A pair may have nested in the park
about five year blocks away, at times. Scrub Jays have been in the area for at
least 40 years. I will eventually post about that species’ increase in the
Portland area at some point.
Jeff
On Sep 30, 2021, at 3:44 PM, canyoneagle ("canyoneagle")
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
Jeff, perhaps it is because of Crows and squirrels as you say. I don’t know
if my experience in the 1990s in Virginia would mean anything, comparing it to
your area in the 2020s, but here goes. I lived in Vienna, VA for 19 years.
Vienna is a suburb of Washington, DC, a very developed urban/suburban area. At
that time the population of the DC area was about 5.5 million people. We chose
our house because it backed up to a strip of woods with a small creek running
through it. The woods was pretty good habitat for wildlife, including many
Eastern Gray Squirrels. There were 10-20 in my yard most of the time. My high
count for squirrels (all in view at one time) was 44! Being a wildlife
gardener, over about 10 years I transformed that typical suburban yard into
good wildlife habitat, so the birds and critters felt comfortable in my yard.
I also fed birds, so that attracted the critters as well. The result was,
plenty of birds and squirrels, and also deer, foxes, raccoons, opossums, and
rats, of course. Occasionally a roaming cat or dog would show up, but not that
many, surprisingly, given that coyotes were rare there. The Town of Vienna had
an ordinance against letting cats and dogs run loose, so perhaps that helped a
bit. There were nesting birds in my yard and/or the woods, including Robin,
Cardinal, Sparrow/Towhee species, Blue Jay, Finch species, Carolina Chickadee,
Tufted Titmouse, Carolina Wren, Catbird, Mockingbird, and more. There were
also many thousands of Crows in the area, in massive roosts. I would have
hundreds of Crows streaming over my house daily as they flew to/from their
roosts. Most days they staged in the woods for a while and there could be 50
or more in the trees before flying on to their roosts. There were also nesting
Crows in the woods. Sometimes I got lucky and I could watch their nest from my
living room window. However, the Corvid scene changed when people who lived
near the large roosts started complaining about them. After public hearings,
at which I spoke against exterminating the Crows, the people in charge voted to
go ahead with poisoning the Crows coming to the roosts. Not long after that,
West Nile disease hit that area. Between the poisoning and West Nile, Crows
disappeared. I had zero Crows in or over my yard for more than two years. My
many Blue Jays also disappeared, I assume because West Nile disease killed
them. During those Corvid-less years I didn’t notice any dramatic difference
in numbers of Robins or other nesting birds and their offspring that frequented
my yard, and I watched birds in my yard pretty closely. Not scientific, I
know, but it is what I observed in my little patch, sort of how you are going
by an observation in your little patch. Perhaps if West Nile disease had
killed the squirrels too, there would have been a noticeable difference in
numbers of nesting birds/offspring, I don’t know. Perhaps my experience
means nothing regarding your patch, but thought that I would mention it, fwiw.
Lori Markoff -----Original Message-----
From: boo-bounce@xxxxxxxxxxxxx <boo-bounce@xxxxxxxxxxxxx> On Behalf Of Jeff
Gilligan
Sent: Wednesday, September 29, 2021 8:41 PM
To: boo <boo@xxxxxxxxxxxxx>
Subject: [boo] the suggestion that the absence of earth worms was a factor in
robin decline I am stepping away from that theory. Although earth worms had
not been detectable for months, following the recent heavy rains, there were a
lot in some yards last night. That written, during the long hot summer, they
would not have been available. In the past I saw them all summer long.
Despite that, I think the causes are the crows and squirrels that were not
formerly present. POST: Send email to boo@freelists.orgHELP: Contact
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