Date: 12/5/17 9:28 pm
From: Richard Hoyer <birdernaturalist...>
Subject: [AZNMbirds] Red Crossbills in Tucson – Documenting the Types
Dear Birders,

In the past three weeks that I've been home from tours, I've scarcely been able to sit for more than 30 minutes in the back yard without hearing a RED CROSSBILL fly over. That there is a serious irruption going on is an understatement. As many of you know, there are multiple "types" of Red Crosbills that represent what will eventually be recognized as valid species. Only one so far, Type 9 from SE Idaho, is offically split (as Cassia Crossbil), but only because its limited distribution has allowed it to be researched to an extreme. The remaining 10 types are not as limited in distribution, some rare and very nomadic, and so it will a while before enough vocal, physical, and genetic data has been collected to prove that they are also each valid species. Even then, unless you have absolute pitch memory like Diane Schuur and know immediately which type you're hearing, you'll probably want to record the calls and later look at the sonogram to determine which type (species) you heard.

Not all of us have a good digital recorder and professional microphone. I have an Olympus LS14 and Sennheiser ME67, which is well below the level of a professional setup. But any smart phone or digital camera with video function (just leave the lens cap on; you're not trying to video the birds) can record enough sound to determine which type you have seen and heard.

Once you have a video or sound file, upload it to your home computer and open it with the free Audacity software and compare the sonogram with the known types. The most useful synopsis is the article by Matt Young and Tim Spahr at

From my yard in north-central Tucson I have documented Types 2 (Ponderosa Pine), 3 (Western Hemlock), and 4 (Douglas-fir) in the past several days. Type 4 predominates each day, with only one each of Types 2 and 3. I also recorded one crossbill flying over the E side of the University of Arizona that proved to be Type 5 (Lodgepole Pine). Then just today birds in the Santa Catalina Mountains proved to be Type 6. In other words if you are paying attention, you could be seeing and hearing five kinds of Red Crossbill in SE Arizona right now.

If you have difficulty seeing the differences in the sonograms of each call note, feel free to email me your sound file, and I'll be happy to have a look at it.

Good Birding,

Rich Hoyer
Tucson, Arizona
Senior Leader for WINGS

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