I'll second what Dave said.
I talked to folks and/or visited places in WY, CO, UT, and MT last fall and
couldn't find any good cone crops -- there really seems to have been a
massive failure of cone crops across much of the west. I've been amazed at
the extent to which type 2 and 4 have dispersed this year. Currently, there
is a big concentration of both types in the red and jack pine forests of
the upper Great Lakes region. Folks in my hometown in southern Michigan
have seen more type 2 than I have this winter!
Initially, I suspected that a lot of type 2 would stick around and try to
eek out an existence on lodgepole pine, which basically always has a good
cone crop, given that many trees are serotinous and thus retain cones with
seeds until a fire occurs. After all, type 5 (the second most common type
in our region) is a lodgepole pine specialist, and has a similar bill size
to type 2, so why wouldn't a bunch of type 2 stick around? However, that
really does not seem to have happened -- the few type 2 that did stick
around this year have really been hitting feeders hard and have been doing
so for much of the winter (look at the enhanced media reports of crossbills
in eBird throughout the Rockies -- almost every time the birds have been
identified as type 2, they are on feeders, not conifers). A not
insignificant number of birds further out on the plains have even taken to
feeding on the sunflower seeds Dave mentioned.
So why did this happen? Why didn't type 2 simply opt to hang out in
lodgepole pine all winter, instead of traveling well over 1,000 miles to
Wisconsin, spending the winter acting like goldfinches and siskins in
Oklahoma, or hanging out at feeders along the Front Range? As the movement
of crossbills was really getting underway in the fall, I gathered some data
on type 2 that were feeding on lodgepole pine here in the Laramie Range. On
average, type 2 birds were extracting seeds at a rate 30% lower than type 5
feeding at the same time/place. It's not easy to make a living in a cold,
high elevation pine forest with short day lengths when you're competing for
food with a close relative that has a 30% advantage. The bill differences
between most call types may be small, but they really do make a huge
difference when it comes to their ability to feed on different conifers.
I don't have much to say about siskins, except that I find Dave's
observations fascinating and will be emailing him soon about that. However,
one thing struck me this winter compared to last year. Throughout the high
elevations of the Rockies last winter, there was an excellent cone crop of
blue and Engelmann spruce, which siskins readily feed on. At the time, I
was doing fieldwork on crossbills in the Snowy Range west of Laramie. By
February 13, large numbers of siskins had returned to the Snowies and were
singing and courting like crazy. This year, in the absence of such a
bountiful cone crop, the first siskins appeared on March 29, at a feeder in
Laramie, and they didn't show up in the mountains until much later.
And before I forget, I'd be very appreciative if you'd email me about the
cone crops in your area, Leon. The situation is not looking terribly good
in the Laramie Range this year.
On Thursday, May 17, 2018 at 9:37:25 PM UTC-6, Dave Leatherman wrote:
> Leon et al,
> Cody Porter, crossbill student at U of WY, reported to me last fall he had
> observed a general failure of essentially all conifer cone crops in the
> mountains of WY last year. I suspect a similar thing happened in CO since
> such large phenomena across tree species tend to be regional. That
> probably explains the major incursion of Red Crossbills that included at
> least two Types (2 which is ponderosa pine dependent, and 4 which is
> Douglas-fir dependent) into lower elevations, including the Eastern Plains
> of CO and beyond. Since cone crops are irregular to start with and take
> years to produce, I can see why the crossbills that were doing well on
> local, low-elevation resources would linger until now.
> As for siskins, I don't know how long it has been going on but they have
> nested for one cycle in Lamar in late spring-early summer for several
> years. My theory is that the massive wild sunflower crop on the plains
> most winters, followed by abundant Siberian elm and dandelion seed in
> April, allows them to do well out there and it is cool enough in
> spruce-populated cemeteries out East to allow them to pull off the first
> brood. I also think they move to the cooler mountains in summer (June?)
> for brood #2.
> That's my take on your observations/questions.
> Dave Leatherman
> Fort Collins
> *Sent:* Thursday, May 17, 2018 9:14 AM
> *To:* Cobirds
> *Subject:* [cobirds] Red Crossbills, Pine Siskins - Pueblo
> COBirders-- As I reported several days ago, Red Crossbills are visiting
> my back yard regularly, ranging from four to seven birds at a time. It’s
> odd that they would stick around after not having been here before during
> the 47 years we have lived here. Also, the flock of 12 to 15 Pine Siskins
> have been snarfing Niger (aka nijer, thistle) seed continuously for about
> six weeks, much longer than this species has stayed before. Why would
> these irruptive species stick around this year? Soon I will be off to the
> mountains to check on the cone crop, related to the crossbills. Could the
> drought be the cause of the siskins’ extended visit?
> Leon Bright, Pueblo (city/county)
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