How to Know the Birds

• What: Red Crossbill, Loxia curvirostra
• When: Saturday, March 14, 2020
• Where: Heil Valley Ranch, Boulder County Colorado

The plan was solid. Be in the foothills forest by late morning, when the big warm-up would be under way. The skies would clear, temps would quickly rise through the 50s, and photo ops—Steller’s jays, male mountain bluebirds, maybe even a wild turkey—would abound.

That was the plan.

As we approached the trailhead, the temp had dropped, actually, from a morning high in the mid-30s. The cloud deck was hanging at around 6,000 ft., our present elevation. Dense freezing fog reduced visibility to near zero. Like this:

Photo by © Ted Floyd.

Once again, we were reminded that weather forecasting is challenging in and around the steep foothills of the southern Rockies. Okay, we wouldn’t be getting photos of Steller’s jays and such. We wouldn’t be seeing them at all. This was to be an exercise in “ear birding,” as, for example, when these birds flew over, invisible in the pea soup of freezing fog:

Those are sounds of a flock of red crossbills on the wing. I looked down at my wristwatch, wiped the moisture off it, and saw that the hour was high noon. Here’s what things looked like now:

Photo by © Ted Floyd.

I heard some chippering in the general direction of those barely there ponderosa pines, so I went in for a closer look. Yep, a red crossbill, through the filter of my misty camera lens and the fog-shrouded landscape:

Photo by © Ted Floyd.

Case in point: the several flocks of bushtits I heard, and sort of saw, that foggy afternoon in the foothills. When I arrived in northeastern Colorado, 18 springs ago, bushtits were rarities. You could go many months, back in the day, without seeing a flock. Today they are routine, the problematic beneficiaries of human modifications to the landscape and the climate.

Also: the American crows who kept me company on my ramble in the pinewoods. The ornithologist Ken Parkes considered the urbanization of the crow to be the most dramatic ornithological change he’d witnessed in his lifetime. I heard a wild turkey, too, another species that has adapted to urban life. Turkeys and crows and bushtits are appreciably different today than they were a human generation ago.

So are we, we birders and naturalists, which point comes into sharp relief when we reflect on how we engage red crossbills at the present time.

I made a video, not a great one, of that red crossbill feeding in the foliage:

The crossbill is deftly plucking seeds from a ponderosa pine, something that not every crossbill is capable of doing. The ones that do it the best are called “ponderosa pine red crossbills,” or “type 2 red crossbills.” We know that these ponderosa pine specialists have notably large bills like the bird in the video. We also know that their flight calls are distinctive, being sharply down-slurred with a kink in the middle. Like this:

Spectrogram by © Ted Floyd.

That’s a snippet from the sound spectrogram of the flock we listened to above.

It all adds up. This is a type 2 red crossbill because it sounds like one, looks like one, and acts like one. But check this out: We didn’t know any of that stuff when I started birding close to 40 years ago. Bird populations are changing, and so is our knowledge of bird populations.

A final thought. We ourselves are changing.

I don’t hear birds the way I used to. My eBird checklist for the morning has no golden-crowned kinglets and brown creepers, high-pitched birds I don’t hear as well as I once did. I suspect those species were there but undetected by me. But that’s not what I’m getting at.

When I heard those crossbills fly over, I was nearly certain they were type 2s. How did I know that? In my teens and early 20s, saying “type 2” crossbill would have been like saying “pleerfa snirns t’ho pisby.” It wouldn’t have meant a thing to me.

Here’s how I knew. In my mind’s eye, I could see their down-slurred spectrograms, with the kinks halfway through each flight call. Emphasis on “see.” I hear a sound, and something goes off in the visual cortex of my occipital lobe. Learned synesthesia, we now know, is a powerful method for learning. Non-Western cultures do it better than we do, but the good news is: With a bit of self-discipline, the habit can be acquired.

There are birds, and that’s wonderfully encouraging. Even more wondrous: We are engaging them with improved understanding and newfound wonderment.

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