This crossbill-sunflower business is all very interesting. Being true nomads, crossbills go wherever necessary to find food, be it conifer seeds or something else. Summer is between last year's mostly-depleted conifer seed crop and this year's developing one, which is just now beginning to mature/be available. Crossbills can raise multiple broods in a given year and can nest in any month. Food sources, including cone crops and others, fluctuate wildly from year to year. And while a crossed beak would seem to indicate specialized feeding, Dave and Carol Steingraeber's experience of red crossbills obtaining nyger fruit ("seed") from tiny openings via their tongue is informative. Crossbills are amazingly clever, both in the way they utilize their unique beak and the ways they get around its limitations! Put all these factors together and probably nothing they do should surprise us.
My take is that, yes, it appears to have been a productive year for certain types of red crossbills. Yes, juveniles seem to hang together. Yes, perhaps their straight, barely curved, and/or newly crossed bills might make sunflower seed from flowers easier to obtain than conifer seed. Yes, all the rain down low this year grew a TREMENDOUS crop of sunflowers. Yes, still lots to observe, learn, and report. I think I am hearing two types of red crossbills in urban Fort Collins (2s for sure, and maybe 4s?), both getting sunflower seed from flowers. I know, I know, record them, edit the giant resultant files, create sonograms, get confirmation of the types. I wish I knew how, which is nobody's fault but my own. Just haven't paused to figure it all out for my clunky phone. Please tell me, which paper cup has the record button, or is it on the string?
The next "The Hungry Bird" article in the upcoming fall issue of "Colorado Birds" happens to be about what crossbills eat other than conifer seed. Of course, the article was "in the can" before all this flurry of sunflower seed-eating we are witnessing. The article gives this specific issue only minor mention. Such is the nature of our business. We should regret having only partial knowledge and revel in the opportunity to grow it.
Thanks for everyone who has shared their red crossbill sunflower experiences at feeders or at flowers.
Dave Leatherman
Fort Collins
From: Diana Beatty <otowi33.33@gmail.com>
Sent: Wednesday, August 30, 2023 10:27 AM
To: Richard Trinkner <rtrinkner@icloud.com>
Cc: Dave <daleatherman@msn.com>; Cobirds <cobirds@googlegroups.com>
Subject: Re: [cobirds] Red Crossbills & sunflowers
In general, if breeding is successful in significant increases in the population and cone crops are small or depleted, Red Crossbills will erupt beyond usual ranges or habitats and pursue atypical food sources. Red Crossbills tend to wander wherever the food is to be found and so may have less site fidelity than some other species. I suspect the crossbills in the Boulder area had a successful breeding season and have well-enjoyed the local cone crops and now are dispersing due to their increased numbers to take advantage of a wider variety of foods. It has been noted that immature birds sometimes go through a teenager phase where they hang out together more than with the mature birds. But the details about bill development and specific food sources is interesting!
Diana Beatty
El Paso County
On Wed, Aug 30, 2023 at 10:12 AM 'Richard Trinkner' via Colorado Birds <cobirds@googlegroups.com> wrote:
Thanks, Dave, for the report about the crossbills in Fort Collins.
Your post got me wondering:
1. If juvenile crossbills are still developing curved beaks, might that explain why we don't see adults in these flocks feeding on sunflowers? Could the juvenile beaks be more suited to prying seeds from the sunflowers than prying them from pine cones? Or might adult beaks be less suited to sunflowers? (Although many of the juvies I saw yesterday had less curved beaks, several had very curved beaks, so maybe this theory doesn't work.)
2. Is there a shortage of food in the foothills for the juveniles? There have long been sunflowers on the plains, but this is the first time I've seen crossbills encamped at the Community Gardens. (They're still there, as of 6:45 this morning.)
3. Do juvenile crossbills generally separate from the adults and form juvenile flocks?
Here's a shot of one of the juvies yesterday.
Richard
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