As I noted in a guest blog for the Finch Research Network last fall, the story of Cassia Crossbills in Colorado is complicated by the fact that I belatedly discovered a recording of Cassia that I had made in Silverthorne, Colorado in March of 2012, pushing the first known occurrence of the species in Colorado back by nine years.
https://finchnetwork.org/cassia-crossbills-in-colorado-the-mystery-deepens What does that mean, exactly? Heck if I know. But I do think it's another great reason why EVERY birder's first instinct upon hearing crossbills -- anywhere, anytime -- should be to pull out the phone and hit record. Nathan Pieplow Boulder On Mon, Jun 19, 2023 at 4:08 PM David Lawrance <[email protected]> wrote: > Nearly Half of the Cassia Crossbill's Population Could Be Lost After > Wildfire > <https://www.audubon.org/news/nearly-half-cassia-crossbills-population-could-be-lost-after-wildfire> > is a 2020 Audubon article about the Badger wildfire in the South Hills in > the fall of 2020. Christian Nunes reported the first report of 3 birds in > Colorado in Grand County not much later in July 2021. Not that any > conclusions can be drawn from just that, it does suggest a reason to locate > to new lodgepole-rich areas. That cassia crossbills never needed to migrate > doesn't mean that they are incapable of it. > > David Lawrance > Longmont CO > > On Sunday, June 18, 2023 at 4:36:39 PM UTC-6 Ted Floyd wrote: > >> Hey, all. >> >> Motivated by Diana Beatty's COBirds inquiry from earlier today, I quickly >> generated a few eBird range maps. Check it out: >> >> [image: Cassia Crossbill 1900-2000 zoomed in.png] >> *eBird records for Cassia crossbill, 1900–2020.* >> >> [image: Cassia Crossbill 2021-2023 zoomed in.png] >> *eBird records for Cassia crossbill, 2021–2023.* >> >> Zooming out to show the entire Lower 48: >> >> [image: Cassia Crossbill 1900-2020 zoomed out.png] >> *eBird records for Cassia crossbill, 1900–2020.* >> >> [image: Cassia Crossbill 2021-2023 zoomed out.png] >> *eBird records for Cassia crossbill, 2021–2023.* >> >> It isn't too much of an exaggeration to say that much of what we "knew" >> about the Cassia crossbill has been thrown out the window. The conventional >> wisdom not even five years ago was that the species is restricted to just >> two mountain ranges in Cassia and Twin Falls cos., sc. Idaho. But now we >> understand that the Cassia crossbill occupies a larger swath of the >> southern Rockies in c. Colo., encompassing at least Eagle, Pitkin, Park, >> Summit, and Grand cos. >> >> What is it that sc. Idaho and c. Colo. have in common? Answer: lots of >> lodgepole pine and almost no ponderosa pine. Cassia crossbills love >> lodgepole pine. So far, so good. But you knew it wasn't going to be so >> easy. Because what is it that *distinguishes* the mountains of sc. Idaho >> from those of c. Colo.? Well, squirrels are absent from sc. Idaho's >> mountains, yet prolific in the mountains of c. Colo.; good luck finding a >> U.S. Forest Service road or campground in c. Colo. and *not* finding >> buttloads of southwestern pine squirrels. (ICYMI: recent split, now >> *Tamiasciurus >> fremonti*.) You can probably see where I'm going with this: The specific >> epithet, *viz*., *sinesciurus*, of the Cassia crossbill means "without >> squirrels" because our understanding of the evolutionary ecology of the >> species critically depends on there being a landscape without squirrels. >> But that interpretation tidily defenestrates in squirrel-infested c. Colo. >> >> I threw in a tease about ponderosa pine. Cassia crossbills don't seem to >> care about ponderosa pines, but Colorado's widespread red crossbills, the >> type 2, or, ahem, "ponderosa pine," red crossbills, supposedly do. And type >> 2 red crossbills are the numerically dominant crossbills in the mountains >> of c. Colo., cheerfully chowing down on lodgepole seeds, spruce seeds, fir >> seeds, Douglas-fir seeds, Walmart™ and PerkyPet® seeds, and even >> CDOT-proffered potash and magnesium chloride along state highways in the >> region. But not ponderosa seeds because they're not even there. (Okay, >> slight hyperbole. They're in people's yards in some places and, sparsely, >> planted around resorts. Pondos in condos, lol. And a very few in the >> nominal "wild." But ponderosa pines are, practically speaking at an >> ecological level, absent there.) >> >> All of the preceding is a gratifying case study for the power of eBird to >> advance and even substantially revise our understanding of bird biology. >> All it takes is a modicum of care and discipline. Note: not necessarily >> skill and experience; those are "nice to have," "icing on the cake." The >> biggies for field ornithology are care and discipline. What's so great >> about eBird here in Colo. is that records of Cassia crossbills, as well as >> records of red crossbills at the level of the "type," now *require* audio >> with diagnostic spectrograms. The word "diagnostic" needn't be scary. >> Here's a pair of barely audible type 2 (ponderosa pine) red crossbills that >> I recorded as they were receding fast in the drizzle high above the, er, >> lodgepole pine forests of c. Gilpin Co. a couple days ago: >> >> https://macaulaylibrary.org/asset/585935691 >> >> It's really a piece-o'-crap recording. Don't bother trying to hear it. >> That said, the spectrogram of the flight call, strongly descending with a >> kink, or crook, around 4 kHz, is completely diagnostic for type 2. As Donna >> Dittmann once said, "If I can do this [use technology], anybody can do >> this." Well, the only birder more tech-averse than Donna is Yours Truly. >> >> A whole lot of us will be in c. Colo. in just about a month for the joint >> meeting of Colorado Field Ornithologists (CFO) and Western Field >> Ornithologists (WFO). Literally hundreds of birders will be within earshot >> of crossbills almost continually. At the very least, we'll all be hearing >> type 2 red crossbills. Type 5 red crossbills should be up there, too, and >> perhaps type 3 and type 4 red crossbills, as well. Especially where there >> are spruces near timberline, white-winged crossbills absolutely should be >> looked for. And if the summer of 2023 proves to be anything like the >> summers of 2021 and 2022, then we can be hopeful for encounters with Cassia >> crossbills. >> >> BUT... >> >> AND... >> >> We need to document it all. Photos and especially videos of crossbills >> feeding are exceedingly valuable. And what we're really after is as much >> audio documentation as possible of flight calls. Cellphones are eminently >> up to the task; just press the red button, it's that easy. Also, you can >> extract audio from video made with even the most basic of digital cameras. >> Best of all, you don't even need to know what you got. If you're not >> certain (Floyd raises his hand, half the time he's out there...), just >> upload your media as "Red Crossbill" or "Red/Cassia Crossbill" or >> "crossbill sp."—those are all valid eBird "taxa," and it is an excellent >> idea to use them when you're not sure—and an eBird reviewer or other expert >> will swoop in and help you with the ID. >> >> In a little more than a month, we may know a lot more about crossbill >> biology than we do right now. How cool is that! I hope somebody writes up >> the analysis for CFO's journal *Colorado Birds* and for WFO's journal >> *Western >> Birds*. Just take pictures, make videos, and record audio. Lots of it. >> And, not to go all Leatherman on you, but try to ascertain what the >> crossbills are eating. >> >> We can do this! >> >> Ted Floyd >> Lafayette, Boulder Co. >> > -- > -- > You received this message because you are subscribed to the Google > Groups "Colorado Birds" group. > To post to this group, send email to [email protected] > For more options, visit this group at > http://groups.google.com/group/cobirds?hl=en?hl=en > * All posts should be signed with the poster's full name and city. 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