Cassia crossbill + technology -- Grand County

[Mark Obmascik]

I checked out the Cassia crossbill stakeout feeders north of Granby today and saw many crossbills. 

Can I pretend that these crossbills sounded or looked different than the hundreds I have seen over the years at our home feeders 20 miles away? No.

But there was the Merlin app on my phone, identifying a Cassia crossbill by sound when the birds dived onto the feeders or flew overhead. Merlin did not identify a single red crossbill, though there were times I saw and heard crossbills without a Merlin ID.

There has been some good talk on CObirds lately about the pluses and minuses of technology in birding. Here's a species that I never would have ID'd without tech. In fact, with this bird I'm relying 100 percent on tech for the ID (or a veto from an eBird reviewer.)

Today's experience makes me wonder if all the crossbills I identified at my home feeders over the years were really red crossbills. Next time I'm pulling out my Merlin app and listening.

As a side note, am I correct to remember that this species originally was believed to live in only one limited area in Idaho that was swept by wildfire, and that there were fears at the time that the bird might have been wiped out? And then I remember Christian Nunes camping some years later in summer near Church Park in Grand County (maybe 10 miles from today's feeder site) and identifying Cassia crossbill by sound. I biked many times in that area afterward hoping to see the birds in summer, but nada. 

I salute birders with keen ears, and I salute Merlin.

Here's a pic, not that this matters with this species.

Good birding,

Mark Obmascik

Tabernash, CO

[Peter Ruprecht]

Hi all,

I highly recommend Christian Nunes' overview of Cassia Crossbills in the Fall 2025 CFO Journal: https://cobirds.org/wp-content/uploads/2025/11/2025_CB_59_4_Fall.pdf

Regarding Merlin and crossbills, first note that Cassia and Red are best differentiated by their flight calls. I'm no expert but in June, 2024, I used Merlin on my mediocre cellphone to record quite a few crossbill calls in several locations in S. Idaho. Merlin did not seem to offer ID suggestions very often for Red Crossbill even when a large flock flew over making loud flight calls. It seemed to be more willing to ID Cassias. Maybe this is similar behavior to what Mark reports in CO?

But if you go back and look at the sonogram that Merlin creates (or, if you like a bigger screen, open the recording in an app like Raven Lite, Audacity, or Ocenaudio on your computer) you can visually see the "shape" of the calls and make the ID yourself. Alternatively, the sonograms that are generated from uploaded recordings in eBird these days are usually clear and easy to read. For me personally, it seems prudent to look for this "visual" confirmation before reporting a crossbill species in Idaho or central CO, at least in a lodgepole pine forest. (My ears aren't good enough to tell the difference consistently in the field.)

Of course there's the added twist that Red Crossbills in North America have around 11 different flight call types. You can see sonograms of all of these (plus Cassia) at https://finchnetwork.org/crossbills-of-north-america-species-and-red-crossbill-call-types . I think in Colorado we mostly have Type 2 (ponderosa) and Type 5 (lodgepole). Maybe it's easier just to take Merlin's word for it!

Just for fun, here's a sonogram of a Red Crossbill recorded by a member of the "Marshall Mesa" team on the Boulder CBC last December. You can clearly see the downslur of a Type 2 call.

Peter Ruprecht

Superior

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[Richard - Dick Filby]

Peter,

Many thanks for the FinchNetwork link - a nicely updated version of the earlier 2017 article

By Matthew Young and Tim Spahr 11 Oct 2017

Published here:

https://ebird.org/news/crossbills-of-north-america-species-and-red-crossbill-call-types/? 

Best wishes

Dick Filby

Carbondale, CO

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From: cob...@googlegroups.com <cob...@googlegroups.com> on behalf of Peter Ruprecht <prup...@gmail.com>
Sent: 13 February 2026 03:25
To: Mark Obmascik <mo...@yahoo.com>
Cc: Colorado Birds <cob...@googlegroups.com>
Subject: Re: [cobirds] Cassia crossbill + technology -- Grand County

 

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