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The mockingbird’s Paganini performance with puffed-out chest is one big emphatic come-on, a “Hey, babe, check me out.” Extravagance in nature is so often found in proximity to sex.
Just what makes a song sexy seems to vary from species to species. Female swamp sparrows and domesticated canaries favor trill rates nearing the limit of possible performance, while zebra finches lust for loud songs. Some female songbirds have a soft spot for long or complex songs. Others, such as canaries, are turned on by “sexy” syllables.
Many songbirds have regional dialects with “accents” as distinct as a Boston “Southie” or an Arkansas drawl.
The great tits of southern Germany have a dialect so distinct from the great tits of Afghanistan that the German birds don’t recognize their Middle Eastern relatives.
“Like the allure of a big egg to a chicken.” (As ethologist Niko Tinbergen learned, hens like big eggs: Give a hen a giant egg to sit on, even an artificial one, and she will prefer it to a small egg. In her mind, bigger is better, even if it’s not natural.)
Compare the two spectrograms side by side and the results are clear: No matter how hard the diligent student tries, his replications of his own syllables are wildly variable. The zebra finch’s are nearly identical. In terms of his precision, says Mooney, “the bird is like a perfect machine.”
A typical songbird nestling reaches about 90 percent of his adult weight within the first ten days of his life—an incredibly rapid rate of growth.
well-fed zebra finches copied 95 percent of syllable types from their tutors while underfed birds copied only 70 percent.
In other words, a male bird is deemed only as good as his song. His melody betrays his biography for his entire life.
In fickle environments where capricious weather—erratic rainfall and fluctuating temperatures—made food sources iffy, mockingbirds not only had a bigger repertoire but were better at copying the songs and calls of other species, with truer notes and more consistency. Perhaps a male’s singing skills signal to females that he’s clever enough to cope with unpredictable environments, says Botero. This adds weight to the idea that some aspects of birdsong may provide information about a male bird’s general cognitive skill—and that sexual selection is acting on these signals of intelligence.
Whether female songbirds use male song as a proxy for general smarts remains to be determined. But one thing seems clear: Over evolutionary time, females have shaped the complex, precise, extravagantly beautiful tunes of their kind—and the elaborate brain circuitry required to produce it.
Birds that sing their songs well in spring and fall experience those rewarding chemicals, dopamine and opioids—but in different amounts in each season, and to different ends. Opioids induce not only a feeling of pleasure but also analgesia, says Lauren Riters.
Fall song, she found, is more tightly coupled to opioid release than spring song. As Darwin wrote, “the songs of birds serve mainly as an attraction during the season of love,” but after the season for courtship is over, “male birds . . . continue singing for their own amusement.” Or possibly for the drugs.
This bird is bullish on blue: cornflower-blue tail feathers from a parrot, lavender lobelia blossoms, shiny blue fruits from the quandong tree, purple petunias, and blue delphiniums stolen from a nearby homestead, along with fragments of cobalt glass or pottery, navy blue hair ribbons, bits of turquoise tarp, blue bus tickets, straws, toys, ballpoint pens, that eyeball, and his prize, a baby-blue pacifier pilfered from his neighbor.
“A bird’s nest is the most graphic mirror of a bird’s mind. It is the most palpable example of those reasoning, thinking qualities with which these creatures are unquestionably very highly endowed.” The English ornithologist Charles Dixon wrote that in 1902. Nevertheless, we’ve long assumed that nest building is a purely innate behavior:
No, this strange and elaborate creation, known as a bower, is built for one purpose only—seduction—by a creature of extraordinary craft and intelligence, the satin bowerbird (Ptilonorhynchus violaceus). So remarkable is the bowerbird family that the ornithologist E. Thomas Gilliard once remarked that birds should be split into two groups: bowerbirds and all other birds. Bowerbirds are noted for the hallmarks of intelligence: large brains, long lives, and extended periods of development. (It takes them seven years to mature.) All twenty or so species live in the rainforests and woodlands of New
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If satin bowerbirds favor blue, they reject red. Plop a crimson object down amid the blue ones, and the birds will quickly remove the offender, fly off with it, and drop it at some distance, out of view. Some observers even go so far as to suggest that fouling the bird’s bower with any shred of red will make the bird madder than a wet hen. Why this aversion to red?
In other words, says Keagy, “Smart is sexy!”
Indeed, scientists have trained honeybees to tell a Picasso from a Monet.
This is easy stuff to poke fun at. The idea that birds and bees play favorites with human art looks a lot like anthropomorphism. But Watanabe’s work is less about whether birds prefer Braque to Monet than it is about their powers of acute observation and discrimination of color, pattern, and detail.
Male manakins perform a “jump-snap” display. It starts with a leap between little saplings. Then, midjump, the bird flips its wings upward in a noisy wing snap. On touching down, it quickly swivels its body into a beard-up statuary position to show off its bright yellow beard, or throat feathers. It’s a supremely difficult move, requiring exquisite neuromuscular coordination and great stamina. Think of a gymnast nailing a perfect landing.
They discovered that females prefer males that perform dance moves at a higher speed. But the difference between the beard-up rond de jambe of one male and the next is measured in mere milliseconds. “The capacity of females to discriminate slight differences in male-choreographed motor patterns (dances) has previously been shown only in humans,” say the researchers.
Umwelt, or sensory and cognitive world.
own. Color, for instance, is not a property of the physical world but the fabrication of whatever visual system may process and analyze it. Birds have possibly the most advanced visual system of any vertebrate, with a highly developed ability to distinguish colors over a wide range of wavelengths. We have three kinds of cone cells for color vision in our retinas; birds have four.
NOBEL LAUREATE KARL VON FRISCH once wrote, “Those who consider life on earth to be the result of a long evolutionary process will always search for the beginning of thought processes and aesthetic feelings in animals, and I believe that signature traces can be found in the bowerbirds.”
That a sparrow transported far beyond its known territory seems to know exactly how to get back on course is one of the astonishments of the bird mind. A good memory doesn’t explain it. And neither do theories that focus solely on instinct or eyesight or magnetic cues or sensitivity to the azimuth of the sun.
The ability was once thought to be innate in birds, a matter of instinct. Now we know that bird navigation involves sensing, learning, and, above all, a remarkable ability to build a map in the mind, one far bigger than we ever imagined
So by some measures, yes, they may seem dim-witted. But in truth, they’re far more bookish than you might imagine. They’re handy with numbers, for instance, capable not only of counting (which, granted, a lot of animals can do, including bees) but also of grasping the arithmetic of loss and gain and learning abstract rules about numbers, abilities on par with primates. They can, for example, put images picturing up to nine objects in proper order from lowest to highest number. They can also determine relative probability. In fact, pigeons are better than most people—and even better than some
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Alex, the African grey parrot that Irene Pepperberg so brilliantly studied before his demise in 2007. Alex was not only nearly flawless in stating whether two objects were the same or different with respect to color, shape, or material, but could say “none” if there were no similarities or differences.
Why would the common pigeon shy away from high arboreal perches and favor narrow ledges? Because it descends, like all domestic pigeons, from the wild rock dove, a bird that nests in the sea cliffs and rocky islands of the Mediterranean.
and the Chinese have lately built a force of ten thousand messenger pigeons to deliver military communications between troops stationed along their borders, in case of “electromagnetic interference or a collapse in our signals,” as the officer in charge of the pigeon army explains.
WESTERN SCRUB JAYS—those masters of social trickery—remember not only where they stashed their caches (and who was watching) but also what they stashed there and when. This is important because the scrub jay squirrels away not only nuts and seeds but fruit, insects, and worms, foods that perish at different rates. Cached insects can spoil in days if the temperatures are high enough, while nuts and seeds can last for months. A series of creative experiments by Nicola Clayton and her team at Cambridge University showed that the birds retrieve the more perishable food before it rots, leaving the
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First, it shows that the birds are capable of making choices between targets according to motivation—a cognitive ability in and of itself—and
This raises a troubling question. If our human navigational efforts shape our hippocampus, what happens when we stop using it for this purpose—when we lean too hard on technology such as GPS, which makes navigation a brain-free endeavor? GPS replaces navigational demands with a very pure form of stimulus-response behavior (turn left, turn right). Some scientists fear that overdependence on this technology will shrink our hippocampus.