Saturday, April 11, 2009

Mimus polyglottus

Spring means birds singing. But at 2 AM?

We've been serenaded by a mockingbird for the last week, at all hours, at top volume, mixing samples collected from all over the western hemisphere to create a crazy-wild DJ scene on the premises. The bird is awe-inspiring to say the least, giving pitch-perfect renditions of titmice, crows, blue jays, and frogs, as well as a few call-and-response numbers, among many other turntable classics.

Why? What is the origin of this bird and its behaviors? A recent article in science laid out the DNA-based phylogeny of birds, of which there are over 10,000 species. It upset quite a few previous classifications, and definitively, since sequence-based phylogenies have greater resolution than character-based ones. Mockingbirds reside in the largest group, the passeriformes, along with other songbirds. I had assumed, from its shape, size, flight style, wing bars, and aggressive behavior that they are closely related to jays, which are related to corvids/crows. But not true! Mockingbirds are cousins of starlings, showing that vocal facility, which starlings share in spades, is also a crucial diagnostic trait. Indeed, an incredibly charming book, now out of print, relates how one starling was taught to speak (and sing) passable English.

The study of birds continues to fascinate the evolutionary community, with new specimens of Archaeopteryx being lovingly studied as it becomes common knowledge that birds are our only living connection to the dinosaur lineage. The fossil record in this case, as is true for whales and other organisms, is filling out to give us an ever-fuller account of complexity and gradualism in the history of life. Additionally, studies of bird memory were the first to demonstrate the birth of new neurons in adult brains, concomitant with the memorization of new songs. Subsequent work found the same phenomenon in humans- an important focus of contemporary neurobiology and even stem cell-associated hopes.

Archaeopteryx from the Jurassic (~150 to 200 million years ago).
Note the claws at the end of the wing/fingers.

Mockingbirds have upwards of 150 song samples at their command, and change their repertoires between spring and fall. The function of their singing, other than attracting mates, is not clear. But one could speculate that the high volume and enormous fund of mimicked songs functions to keep other species at bay, creating better-quality territories for the omnivorous mockingbird. The utility of this trait would in turn create a sexual selection rationale for females (who also sing, just not a 2 AM) to select mates with larger repertoires, more accurate reproduction, and higher volume.

As our culture gradually transitions away from the Christian fetishes of false hope, blood, and death at this time of year to the much more ancient themes of life, fertility, and birth, it is wonderous to participate (if unwillingly!) in the rituals of birds who are so diligently and flamboyantly engaged in the tasks of life.

  • Subscription site at Cornell is the leading resource for general bird knowledge.

3 comments:

  1. Burk,

    It is wonderful to hear about the serenade by the awe-inspiring mockingbird. I also enjoy the miraculous diversity of bird-song.

    Your conviction that you have been “serenaded” by a mockingbird and that “the bird is awe-inspiring to say the least…” is a fairly remarkable statement coming from someone who does not believe in objective beauty. I would have expected some kind of technical definition of the dynamics of sound waves and vocal cords or something. “Serenade”? “Awe-inspiring”?

    Oh that I could join you in the enjoying the beauty of the bird-song in some objective way. Too bad we cannot. How tragic is the self-imposed isolation of a relativistic frame of reference which, in its own way is absolute. Too bad the conviction about the sound issuing from the bird could never have according to your standards the ability to inspire you with awe. To say it did would be to attribute to it some objective power to inspire. The conviction of the bird-song’s beauty, if you are being consistent, is trapped in the isolated recesses of your imagination unable to serve as the opportunity to transcend your own ego and objectively communion not only with the bird but others who, I am sure, would share your enjoyment of something objectively real. The statement that there is no such thing as objective beauty is the epitome of pride and unrestrained narcissism.

    One of the most tragic things about all of this is that your convictions seem to “inspire” me to look for a point of disagreement in your blogs. I would like to just enjoy the beauty of the created order in all of its marvelous diversity and elegant order. That, of course, is my problem not yours. But, it is still sad (objectively or subjectively).

    Fr. Thomas

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  2. Hi, Thomas-

    Thank you for your comment, and I am sorry you feel compelled to disagree when you would rather not.

    The rest of your argument is not very clear, but if I may analogize, you would say that an ice cream sundae is delicious due to its objective deliciousness, not due to the subjective pleasure we take in it. Would that be accurate? If someone who hates such sundaes fails to take pleasure in it, then that person would be a failure in the department of recognizing this objective deliciousness, correct?

    I would suggest that the problem of pride is entirely on your side, in trying to claim objectivity (leading to claims of authority) based on your own subjective experiences, biases, and predilections (or those of the traditions you have chosen to join). That is the ultimate problem of the spiritual experience as it translates (or fails to translate) into religious dogma.

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  3. On a lighter side: mockingbird scene from Failure to Launch
    http://is.gd/tiL6
    you kinda would have to see the whole movie but there was some sleep deprivation involved.

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