Bird Brains
from the book, "Our Fascinating Earth"

Our Fascinating Earth

Bird Brains

The wild turkey species that the Europeans discovered in America had been domesticated by the Aztecs several centuries before. The Pilgrims included the turkey as part of the bountiful crop they celebrated at the first Thanksgiving. Benjamin Franklin, characterizing the turkey as a utilitarian, rugged, no—nonsense bird (much like the Founding Fathers themselves), suggested that the wild turkey become the national emblem. He was outvoted by those who favored a more authoritative, higher—flying bird, the American eagle.

The rejection of the turkey as a national symbol is no cause for reproach, for the turkey is not a notably intelligent bird, particularly when young. Newly hatched turkey chicks have to be taught to eat, or they will starve. Breeders spread feed directly underfoot, hoping they will get the idea. Some chicks have to be force—fed before they figure out that this is how they stay alive. During a heavy rainstorm young turkeys look up with their mouths agape; a few have been known to drown during a cloudburst. About rattlesnakes, however, they are appropriately apprehensive. Farmers report that they always know when a snake is on the property because the birds will form a large circle, well out of striking range, around the venomous reptile. The snake seems to fear them.

When it comes to intelligence among birds, competition for last place is keen. Woodpeckers are often overzealous in storing food for the winter. With their picklike beaks they drill out holes in a tree, into which they stuff nuts and acorns, along with an indiscriminate assortment of small pebbles, as winter "food."

Sometimes a particularly vigorous woodpecker, working on a thin softwood tree, manages to bore a hole completely through the tree. But apparently it doesn't notice; in goes acorn after acorn, nut after nut, all of which fall uselessly to the ground on the other side of the tree. Handfuls of acorns and nuts have often been found lying on the ground under woodpecker holes. The birds that do this may starve during a harsh winter. Similarly there was the woodpecker that spent the autumn feeding acorns into a knothole. Unfortunately the hole was in the wall of a cabin, and the woodpecker was never able to retrieve the hundreds of acorns sunk into it.

Then there is the hoatzin, which makes the turkey and the woodpecker seem brilliant by comparison. This bird, about the size of a pigeon, lives in the swampy jungles of the Amazon Valley, always close to water. Although it can fly, it rarely does; instead it spends much of its time in water and has evolved into an excellent swimmer. Its nest is built in low branches only a few feet above the surface of the water. At the approach of an intruder, young and old alike will dive headfirst into the water. This is all right except that all too frequently the gaping mouth of a crocodile waits directly under the hoatzin nest. This seldom deters the not—too—bright bird, which dives anyway — right into eternity.

There is another type of "birdbrain" — not really stupid; rather just plain crazy. Around the middle of October every year, for completely unknown reasons, some ruffed grouse engage in very abnormal bird behavior. This has become known as "crazy season," when many grouse are found wandering aimlessly in an apparently dazed condition up and down streets of midwestern towns. Some wander into barnyards, mingle with, and act like domestic chickens. Others fly at high speed into open windows and fly aimlessly around the room, overturning flowerpots and smashing china. Still others make a deliberate suicide flight against stone walls and other solid objects. A few of the crazed grouse become as tame a kittens and stroll up to some human to have their heads scratched or petted; these often wind up on the dinner table.

Obviously something in their systems promotes this strange and destructive type of behavior. There is no shortage of theories about why it occurs. Several noted ornithologists have suggested that the fermented fruit of some species of plant ripening at that time of the year is the catalyst for their unorthodox behavior. In other words they are all drunk!

No dissertation on not—too—bright birds would be complete without a word about the South American tarpory. A completely immodest bird, it spends most of its day pecking around the forest floor for food. This is not too unusual in itself, except that the bird appears to have an extraordinary digestive system and excretes more or less continuously while it is feeding. Since it is almost constantly on the ground feeding, the tarpory frequently leaves behind itself a twenty—foot trailing ribbon of dung. The tarpory thus becomes an easy mark for predators, who simply follow the dung trail. Easy pickings for the hungry carnivores, because the bird is usually too busy eating to notice that it is about to become dinner itself.