Why Is Vision Considered More Important Than Hearing?

Suppose you’ve just set up a last-minute trip for birding in Manuas, Brazil. It will be your first time in that diverse region, which sits on the border of Amazonia and the Guianan Shield. There are hundreds of species that will be new for you, and so you will have far too many targets to get intimately familiar with before you go. Even the antbirds alone seem too much to deal with ahead of time, given their similar-sounding names, plumages, and voices.

As you prepare there are some species that jump out, though: they are so unique that you only need to see the picture once, read the description a single time, and you will know exactly what you are looking for.

A great example of this that occurs throughout the Amazon basin is the Hoatzin (my favorite all-time bird), a species in a monotypic order that is truly prehistoric, with young that have vestigial claws. They look unlike anything else that flies. Another species that you can find near Manaus, which is less taxonomically unique but equally bizarre, is the Capuchinbird. A singluar member of the Cotinga family, it is large with a featherless, bluish head and orange plumage. This is not a bird that one could confuse with anything else.

Capuchinbird (photo credit: Greg Hume, CC BY-SA 4.0 via Wikimedia Commons)

Unlike the Hoatzin, which only vocalizes by making soft hissing noises, the Capuchinbird has a call that is as unmistakable as its appearance. It has been described as a cross between a chainsaw and a cow, and if you click on the image below, you can listen to a recording on xeno-canto and you will likely agree that this is indeed what they sound like. “Unique” does not begin to describe it.

Click on the image to access the audio. This recording made by my friend and fantasitc birding guide / recordist, Gabriel Leite

Now, let me set up two different, possible scenarios for how you might cross paths with a Capuchinbird on this trip. You decide which you would prefer.

Scenario one: While driving, the guide sees one fly over the road. You stop and scan the trees where it seems to have landed. There it is! You are incredibly fortunate that it pulled up and perched there on the forest edge instead of continuing deep in like it would almost always do. You get it into your bins for a few seconds – it is enough time to verify the size, the color, even the featherless head. Then, just as silently as it appeared, it is gone. You wait and look and listen but there is no indication of it, or any others. Just dozens of different songs and calls. You mark down Capuchinbird on your list and keep going. You may not even think about the fact that you didn’t hear it.

Scenario two: You and your guide start down a dark trail through the thick forest, seeing and hearing a variety of new species: antbirds, trogons, toucans, motmots. After several hours you are still giddy with all these new experiences. Then you hear a sound you had forgotten about – it doesn’t sound at all like any of the vocalizations so far. You recall that you studied it and your guide confirms this when he turns suddenly to you and you both excitedly announce “Capuchinbird!” at the same time. He cups his hands to his ears, making satellite dishes, and determines that the sound is way off the track, perpendicular to the trail. He starts slowly bushwhacking towards it and you follow. There seem to be some distant responses even further ahead, but the bird that you first heard is now very loud: there is no mistaking it. You both scan the dense tree foliage and change angles because you seem to have found the area where it resides, tight in and high up. It keeps calling, loud and immediate; a vibrant hi-fidelity treat for your ears. Then it stops; there is no more, just the Screaming Pihas and other noisy denizens that you’d tuned out as the Capuchinbird dominated your attention. The guide says that “it flew” but you never saw it leave. There are more of them calling in the distance, but the sound is far off – and you see now that there is small river and a fence blocking the way – you will not be going any further in their direction. “Maybe we’ll see them later” the guide says. But you never encounter them again.

Which of these episodes would you chose?

What I have learned in talking to birders is that the first scenario is usually the only one that would permit most of them to count the bird, i.e., tick it off the list as a lifer; they would not do so in the second case. At best they might count it with an asterisk, a note that it was “heard only,” tacitly indicating a kind of inferior or disappointing rendezvous. But I would argue that the experience of the second scenario was by far the richer of the two. You had a close encounter; you experienced not only the call of the bird, but its proclivity to hide, its shy nature. You didn’t see it, and, to the extent that we might infer what the bird intended…. it likely didn’t want to be seen by you anyway. But you had a sensory adventure way beyond that in the first story. Plus, the identification was no less legitimate.

Of course, I’d prefer to get both the sounds and the sights. I want to (and strive very hard to) see birds because they are spectacular. But I sometimes wonder: if I didn’t have a vision issue, would I take the usual approach of most birders and “require” a sighting in order to count the bird and be content? I am not sure, but, probably, yes. And that would be an error.

An upside of being visually disabled that it has helped me to take in the world in other ways. But you don’t need to have terrible vision in order to recognize this for yourself. You can just try an outing where you put the emphasis on the sounds. Do a stationary count in a birdy area with a blindfold on. You might be surprised by the experience.

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