Conservation Guardians of Northwest Illinois

More Field Notes Previous Next

Home  •  Field Notes  • Brown Thrasher

The Retiring Brown Thrasher

Fall 2005 Newsletter

In late April or early May, the male brown thrasher begins his annual performances at our farm. His extended song, sequences of mostly couplets, delights in its diverse nature with buzzes, trills, rising notes, falling notes, some loud, some soft, some crisp, most melodious. One stops work, listening, convinced that there is a message here.

Henry David Thoreau in the “Bean Field” chapter of Walden wrote, “Near at hand, upon the topmost spray of a birch, sings the brown thrasher — or red mavis, as some love to call him — all the morning, glad of your society, that would find out another farmer's field if yours were not here. While you are planting the seed, he cries — ‘Drop it, drop it — cover it up, cover it up — pull it up, pull it up, pull it up.’ ”

Another version of the thrasher song is given by a Mrs. H. P. Cook as one end of a telephone conversation, "Hello, hello, yes, yes, yes, Who is this? Who is this? Well, well, well, I should say, I should say, How's that? How's That? I don't know, I don't know, What did you say? What did you say? Certainly, Certainly, Well, well, well, Not that I know of, Not that I know of, Tomorrow? Tomorrow? I guess so, I guess so, All right, All right, Goodbye, Goodbye."

Mrs. Cook has perfected the syllable structure, yet these translations and descriptions only point up how impoverished is our flat language compared to that of the thrasher with its changing tones, syllables, volume, and cadence. Konrad Lorenz reputedly said that birdsong is "more beautiful than necessary."

So, the brown thrasher sings not only more beautifully but also longer than necessary with many a performance lasting over an hour. Why? Some say to show prospective females their fitness as a partner; repertoire probably increases with age and thus may indicate experience.

As an older male, I can appreciate the female brown thrasher’s preference. Others say the male’s song is an indicator of health, when one considers this 3-ounce bird singing more than 4,000 songs over two hours. Certainly, its song identifies its gender and species and its presence on a territory.

Those that have observed the thrasher believe its song is primarily to attract females, for once courtship begins on the ground, the male’s song from the treetops ceases. His song, though, continues for his potential mate.

A few people have reported that if one can get within 10 to 15 feet of the courting couple and be very still, you may be able to hear the male singing to her, very quietly, almost a whisper. She will listen for a while, then pick up twigs and flutter toward him. He counters by picking up leaves and approaching her. Since their nest is built of a twig layer, then a leaf/grass layer, and finally a softer rootlet / grass lining, their song and dance ends with intimate agreement to nest together.

Their nest is usually close to the ground in the lower branches of a shrub, preferably thorny. They may be drawn to our farm because we have retained a thicket of wild plums and have been losing the battle against multiflora rose in places. Although the low position makes the nest vulnerable, the parents defend it aggressively — Cornell University says the bird has been known to draw blood from human and dog interlopers. Some believe the bird got its common name from the thrashing it inflicts on nest invaders.

After building the nest, both parents share the incubation and care for the young who fledge in less than two weeks. Both parents also care for the fledged chicks for a time, before beginning the other brood of the season. Some thrashers, though, switch mates for this second brood.

The brown thrasher is retiring and secretive; we see them only a few times each season. So, this behavioral information is from other sources, not from observation. As John Burroughs wrote in Fresh Fields, “There is no bird so afraid of being seen, or fonder of being heard.” Although when seen, “brown” hardly describes its rich cinnamon color, especially on a sunny day.

Researchers have conflicting observations as to whether the male still sings after nest-building begins, and through fledging. Our observation is that he doesn’t sing publicly again until July, about the time he’s looking for a second mate and the first brood is on its own.

My guess is that he’s a romantic and whispers snatches of his song to her while she broods.
It is estimated that in one day a single brown thrasher can consume 6,000 insects, found mostly by the bird’s thrashing the leaf layer of the thicket or shrubs. Many of the insects in its diet are agricultural pests. The bird also eats seeds, berries, nuts, and the occasional small amphibian.

Cornell University describes the brown thrasher’s status as “Populations declining slowly throughout range, perhaps because of the maturation of shrublands in the East and the elimination of fencerows and shelter belts in the Great Plains.” The Pennsylvania Game Commission estimates that brown thrasher populations have declined 4% per year since the 1960’s due to habitat loss as well as cowbird parasitism.

The Mimid family of birds includes the northern mockingbird, the catbird, and the brown thrasher. While the name Mimid hints at mimicking of other birds’ songs, ornithologists prefer the term “vocal appropriation” since these Mimid birds combine songs into their own repertoire, rather than deceiving by singing only a single song.

Texas birder Ruth Beasley compares these three birds, “Like their official mockingbird and catbird kin, brown thrashers have remarkable vocal abilities. Mockingbirds are known for mimicking other birds, reciting long lists of birdsong not their own. Catbirds do this too, mixing in renditions of croaking frogs, squawking chickens, and as you might expect, cats.

“What sets the brown thrasher apart is a propensity for improvisation. Mockingbirds and catbirds, for all their virtuosity, sing their songs the same way every time. A brown thrasher sings a phrase twice or three times, tinkers a bit and sings it again in its slightly altered state ... but what drives a thrasher to continually improvise does not seem clearly understood.”

Excuse my anthropomorphism, but for me, none of the above explains this little creature’s passion for singing. It can’t be an obsessive compulsion, for he innovates. Could he be describing his travels by naming all of the other birds he has encountered? Could he be describing his southern U.S. wintering ground, to attract a female from the same area?

Could he be the avian Homer (not Simpson, but of Iliad fame) in trying to continue an oral history? Or, could he merely love to sing? Also, although he appropriates or copies other birds’ songs, he inserts his own phrases amidst them. Are those unique phrases footnotes, or locations, or behavioral comments about other birds?

Of course, we cannot dismiss these birds as copiers. Let’s consider folksinger Pete Seeger’s comment, "Plagiarism is basic to all culture." Further, he was known to remark that in learning so many folksongs over the years, he couldn’t tell when something he’d written was original.

In this article, I’ve followed the brown thrasher’s lead by including the voices of many other sources, mixed amid my own thoughts. I’ve tried to cite my sources, and for all we know, the brown thrasher does, too.