A mockingbird had set claim to a cottonwood, and on the top branch, it excitedly recited an impressive repertoire of songs. One outburst after the other came in rapid succession, and each one a unique creation, often of some sound it had memorized. One observer recorded 32 songs of different birds it imitated in ten minutes, and some report up to 400 songs may be mastered during a nesting season! It sings by streetlights, too!
Why does the mockingbird imitate sounds? The one I saw down by the riverside was probably singing in conjunction with a nest hidden away nearby. "The territorial imperative." Why does any bird sing? It is usually an announcement of a boundary claim or to attract a mate, although some birds such as the American Dipper seem to sing for the pure joy of singing, even in winter. Many birds seldom make any sound, other than a defiant squawking in the case of egrets and herons.
According to an article, "How Does a Mockingbird Know What to Sing Next?", published in the Birds and Blooms magazine, "The male mockingbird does most of the singing, especially during the mating season when he uses his whole songbook of medleys to lure a mate. To a female, a vast repertoire suggests he is wise to the world, has survived for a while and has established a territory with plenty of food."
"A mockingbird can imitate more than just other birdcalls. It can also mimic squirrels, frogs, crickets, sirens, bells, home alarms, a rusty gate and even the whirring and squeaks of a washing machine.... No other bird matches the imitating talents of the mockingbird."
Some birders are expert in distinguishing bird calls, but unless you're an old hand, you can be startled by the mockingbird's mimicry, or even the cry of the Red-tailed Hawk emitted by a Steller's Jay! Most sounds of the wild are predictable, and you can rely on that connection to the expected stability of nature ... except for the mockingbird mimics.
The whole outdoor field is a mass of churning sound makers - even the power of plant growth - if you can tune in to that frequency. So many things are beyond the hearing capabilities of mankind, especially those with worn-out hearing like mine. It is something like the frequencies of light, and there are many intensities we may not be able to detect at all.
There are many mysteries swirling around the universe and around our ears and eyes, leaving us to grope rather feebly through the mists of time. I was reminded of this by a visit to my cousins in Arkansas one time, when in the evening, I heard something like a distant train roaring on the horizon. When I stepped outside, I was overwhelmed by an almost deafening chorus of insect sounds, an arthropodial symphony letting it all out in the evening as if each had a story to tell! I had almost forgotten that crickets, katydids, cicadas, and the like could be so loud, even though I had experienced that insect clamor in Missouri as a boy. An evening in California is relatively silent, except for tree frogs in the spring and a few crickets in the summer. Insects seem to love that hot, humid Midwest summertime, especially the silent chigger! One reason is that California evenings are on the whole cooler than that eastern cooker. Insects like it hot.
There is "a certain pleasure in the pathless woods / A rapture on the lonely shore (I love not man the less / But nature more." [Lowell]), and the sounds that go with that outdoor ecstasy are part of the allurement to experience those sensations over and over again.
Out in the woods, you can be startled, especially at night, by the wail of a coyote, or the hoot of an owl, the scream of a mountain lion, and the mating call of the Pied-billed Grebe is quite a ruckus. You won't forget your marsh excursion if you hear the crescendo of the grebe and Common Loon. Most birds are more vocal at mating time when all precautions and sensibilities are laid aside.
On our increasingly congested planet, one often has to sort out the mechanical from the natural sounds. Other than the chattering rapids of the river, one day there was an additional sound that I couldn't distinguish, and on investigation, I discovered a fisherman tucked away in the thickets with his radio churning out some weird song. There are those who go to the woods to hear the sounds of the wild, and there are those who like to be reassured by the metallic clicks of manmade compositions.
"As long as I live, I'll hear waterfalls and birds and winds sing. I'll interpret the rocks...and get as near the heart of the world as I can." --John Muir
May 2, 2002