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


________________________________
From: cobirds@googlegroups.com <cobirds@googlegroups.com> on behalf of Leon 
Bright <urra...@comcast.net>
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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