第1个回答 2015-04-21
The Singing Life
Looking deeper into bird songs
For half my birding life, I’ve been trying to learn bird songs. They’re not so easy as visual images. Not so simply reducible to key phrases (yellow in front of the eye, keel-shaped tail, white rump). Often forgettable, at least for a person who has never demonstrated a good ear or musical talent. I’m still fooled sometimes into taking a scarlet tanager for a robin. And every spring I must learn the warblers’ songs all over again. It’s a task I enjoy, an annual initiation that keeps me connected to the earth.
I know birdsongs the way I know French and German. I can often tell which foreign language I’m hearing, and I comprehend merci and nein, but I can’t understand a sentence. And that’s about where I think I am with bird songs. Still, I’m grateful for what I do recognize.
Walking along the brushy trail beside certain a willow thicket on a late summer morning, when most of the birds had stopped singing, I heard a song from deep in the foliage. It was scratchy, rapid: Wouldja switch a witch’s widget witz a switch? Only half a song, really. The full version would have followed up with the answer: Witches switch a scritch’s stitches witz a chew! But even half a song was enough to tell me that the invisible singer was the question-and-answer bird, the Bell’s vireo. (Spectrogram of that bird's song above.)
Born to recognize bird songs
It seems rather wonderful to me that a bird declares its identity with every utterance, and that our human ears and brains are built to sort out such sounds and recognize the singer. Lately I’ve come to realize, though, that I’ve barely begun to study bird sounds, and that it’s possible to learn much more than simply which species is singing.
Donald Kroodsma’s ear-opening book, The Singing Life of Birds, made me realize that I’d been simplistically identifying birds by their songs and letting it go at that, like some life-listers who glance at a bird only long enough to name it and rush on. Kroodsma listens deeply into the lives of birds, gaining new insights from their songs. I want to do that too.
The Raven key
After I read Kroodsma’s book, I got some recording equipment and started going out every day to capture the songs of the morning. Suddenly, every robin, titmouse, and cardinal was new and fascinating. I downloaded Raven Lite (free, from the Cornell Laboratory of Ornithology) into my computer. Among other things, Raven translates my recordings into pictures, called spectrograms, which show details in the songs that I didn’t notice in the field. It also lets me slow a recording down to further reveal fine details too brief for the human ear.
What a revelation! Out of my own spectrograms jumped field sparrows, meadowlarks, and yellowthroats. (See thewichity- wichity- wichityof the common yellowthroat at right.)
As I learned the shapes of their songs, I could see at a glance which species sang on each recording, even before I played the selections. I relished seeing subtle details, such as the difference between the question and the answer of the Bell’s vireo.
Hearing with your eyes
Kroodsma says that he hears with his eyes, letting the birds’ spectrograms show him what he would not have discriminated with his ears alone. I too found that my eyes started educating my ears. Taking Kroodsma’s lead, I used Raven to chart scarlet tanager songs frombirdsong CDs I’d purchased and compared them to spectrograms of my own robin recordings. Once I saw the difference in their timing and noticed the robin’s odd shrieky note spliced in between the musical ones, I started hearing the difference outdoors, too. I don’t think I’ll ever confuse scarlet tanager with robin again.
Kroodsma found that he could tell some birds from others of their species by the variation in their repertoires. That suggests the possibility of getting to know my neighboring birds better than I’ve ever done before. I can hardly wait for next spring. If the five singing male Bell’s vireos I listened to this summer come back, I’d like to see if I can learn to distinguish them as individuals, to see where they first show up in spring, where they nest, and how far they stray from their home territories. Now that’s going to be fun.
— Diane Porter本回答被网友采纳