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. 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