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)
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
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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