Arthur Morris/VIREO
Blue jay
Jenny Warburg for The New York Times
Dr. Erich Jarvis, with a zebra finch, says some birds are naturally smarter than others.
Posted on 02/02/2005 11:32:44 PM PST by neverdem
Birdbrain has long been a colloquial term of ridicule. The common notion is that birds' brains are simple, or so scientists thought and taught for many years. But that notion has increasingly been called into question as crows and parrots, among other birds, have shown what appears to be behavior as intelligent as that of chimpanzees.
The clash of simple brain and complex behavior has led some neuroscientists to create a new map of the avian brain.
Today, in the journal Nature Neuroscience Reviews, an international group of avian experts is issuing what amounts to a manifesto. Nearly everything written in anatomy textbooks about the brains of birds is wrong, they say. The avian brain is as complex, flexible and inventive as any mammalian brain, they argue, and it is time to adopt a more accurate nomenclature that reflects a new understanding of the anatomies of bird and mammal brains.
"Names have a powerful influence on the experiments we do and the way we think," said Dr. Erich D. Jarvis, a neuroscientist at Duke University and a leader of the Avian Brain Nomenclature Consortium. "Old terminology has hindered scientific progress."
The consortium of 29 scientists from six countries met for seven years to develop new, more accurate names for structures in both avian and mammalian brains. For example, the bird's seat of intelligence or its higher brain is now termed the pallium.
"The correction of terms is a great advance," said Dr. Jon Kaas, a leading expert in neuroanatomy at Vanderbilt University in Nashville who did not participate in the consortium. "It's hard to get scientists to agree about anything."
Scientists have come to agree that birds are indeed smart, but those who study avian intelligence differ on how birds got that way. Experts, including those in the consortium, are split into two warring camps. One holds that birds' brains make the same kinds of internal connections as do mammalian brains and that intelligence in both groups arises from these connections. The other holds that bird intelligence evolved through expanding an old part of the mammal brain and using it in new ways, and it questions how developed that intelligence is.
"There are still puzzles to be solved," said Dr. Peter Marler, a leading authority on bird behavior at the University of California, Davis, who is not part of the consortium. But the realization that one can study mammal brains by using bird brains, he said, "is a revolution."
"I think that birds are going to replace the white rat as the favored subject for studying functional neuroanatomy," he added.
The reanalysis of avian brains gives new credibility to many behaviors that seem odd coming from presumably dumb birds. Crows not only make hooks and spears of small sticks to carry on foraging expeditions, some have learned to put walnuts on roads for cars to crack. African gray parrots not only talk, they have a sense of humor and make up new words. Baby songbirds babble like human infants, using the left sides of their brains.
Avian brains got their bad reputation a century ago from the German neurobiologist Ludwig Edinger, known as the father of comparative anatomy. Edinger believed that evolution was linear, Dr. Jarvis said. Brains evolved like geologic strata. Layer upon layer, the brains evolved from old to new, from fish to amphibians to reptiles to birds to mammals. By Edinger's standards, fish were the least intelligent. Humans, created in God's image, were the most intelligent. Edinger cut up all kinds of vertebrate brains, noting similarities and differences, Dr. Jarvis said.
In mammals, the bottom third of the brain contained neurons organized in clusters. The top two-thirds of the brain, called the neocortex, consisted of a flat sheet of cells with six layers. This new brain, the seat of higher intelligence, lay over the old brain, the seat of instinctual behaviors.
In humans, the neocortex grew so immense that it was forced to assume folds and fissures, so as to fit inside the skull.
Birds' brains, in contrast, were composed entirely of clusters. Edinger concluded that without a six-layered cortex, birds could not possibly be intelligent. Rather, their brains were fully dedicated to instinctual behaviors.
This view persisted through the 20th century and is still found in most biology textbooks, said Dr. Harvey Karten, a neuroscientist at the University of California, San Diego, and a member of the consortium, whose research has long challenged the classic view.
There is a bird way and a mammal way to create intelligence, Dr. Karten said. One uses clusters. One uses flat sheet cells in six layers. Each exploits the basic design of having a lower brain and a higher brain with mutual connections.
In the 1960's, Dr. Karten carried out experiments using new techniques to trace brain wiring and identify the paths taken by various brain chemicals. In humans, a chemical called dopamine is found mostly in lower brain areas, called basal ganglia, which consist of clusters.
Using the same tracing techniques in birds, Dr. Karten found that dopamine also projected primarily to lower clusters and no higher. Later studies show numerous similarities between clusters in the mammalian brain and lower clusters in the avian brain. Experts now agree that the two regions are evolutionarily older structures that lie underneath a newer mantle.
Where the experts divide is on the question of the upper clusters in a bird's brain. Agreed, they are not primitive basal ganglia. But where did they come from? How did they evolve? What is their function?
Dr. Karten and others in the consortium think these clusters are directly analogous to layers in the mammalian brain. They migrate from similar embryonic precursors and perform the same functions.
For example, in mammals, sensory information - sights, sounds, touch - flows through a lower brain region called the thalamus and enters the cortex at the fourth layer in the six-layered cortex.
In birds, sensory information flows through the thalamus and enters specific clusters that are functionally equivalent to the fourth layer. In this view, other clusters perform functions done by different layers in the mammal brain.
A second group, including Dr. Georg Striedter of the University of California, Irvine, a consortium member, believes that upper clusters in the avian brain are an elaboration of two mammalian structures - the claustrum and the amygdala. In this view, these structures look alike in bird and mammal embryos. But in birds they grow to enormous proportions and have evolved entirely new ways to support intelligence.
In mammals, the amygdala is involved in emotional systems, Dr. Striedter said. "But birds use it for integrating information," he said. "It's not emotional anymore."
Meanwhile, examples of brilliance in birds continue to flow from fields and laboratories worldwide.
Dr. Nathan Emery and Dr. Nicola Clayton at the University of Cambridge in England study comparisons between apes and corvids - crows, jays, ravens and jackdaws. Relative to its body size, the crow brain is the same size as the chimpanzee brain.
Everyone knows apes use simple tools like twigs, Dr. Emery said, selecting different ones for different purposes. But New Caledonian crows create more complex tools with their beaks and feet. They trim and sculpture twigs to fashion hooks for fetching food. They make spears out of barbed leaves, probing under leaf detritus for prey.
In a laboratory, when a crow named Betty was given metal wires of various lengths and a four-inch vertical pipe with food at the bottom, she chose a four-inch wire, made a hook and retrieved the food.
Apes and corvids are highly social. One explanation for intelligence is that it evolved to process and use social information - who is allied with whom, who is related to whom and how to use this information for deception. They also remember.
Clark nutcrackers can hide up to 30,000 seeds and recover them up to six months later.
Nutcrackers also hide and steal. If they see another bird watching them as they cache food, they return later, alone, to hide the food again. Some scientists believe this shows a rudimentary theory of mind - understanding that another bird has intentions and beliefs.
Magpies, at an earlier age than any other creature tested, develop an understanding of the fact that when an object disappears behind a curtain, it has not vanished.
At a university campus in Japan, carrion crows line up patiently at the curb waiting for a traffic light to turn red. When cars stop, they hop into the crosswalk, place walnuts from nearby trees onto the road and hop back to the curb. After the light changes and cars run over the nuts, the crows wait until it is safe and hop back out for the food.
Pigeons can memorize up to 725 different visual patterns, and are capable of what looks like deception. Pigeons will pretend to have found a food source, lead other birds to it and then sneak back to the true source.
Parrots, some researchers report, can converse with humans, invent syntax and teach other parrots what they know. Researchers have claimed that Alex, an African gray, can grasp important aspects of number, color concepts, the difference between presence and absence, and physical properties of objects like their shapes and materials. He can sound out letters the same way a child does.
Like mammals, some birds are naturally smarter than others, Dr. Jarvis said. But given their range of behaviors, birds are extraordinarily flexible in their intelligence quotients. "They're right up there with hominids," he said.
Arthur Morris/VIREO
Blue jay
Jenny Warburg for The New York Times
Dr. Erich Jarvis, with a zebra finch, says some birds are naturally smarter than others.
ping
You can be "bird brained" or "as wise as an owl!"
Thanks for posting this. My Sun Conure would agree heartily that birds are intelligent, and I'd second the motion.
Until having a bird for a pet, I used to think how dumb it would be - after all, how much fun could a bird be? Damn, they're like raising children. They learn things so fast, they become bored so easily if not mentally challenged, and they learn how to manipulate humans so early that it amazes me.
Now I look at my dog and think: So what can you SAY to me? My bird talks. My dog doesn't. Which one is smarter? The bird, by leaps and bounds.
So when do they figure out the kind of intelligence an Irish setter has?
I resemble that remark.
Go Eagles!
Thank you. As a parrot owner, I am always looking to better understand birds and how they act, perceive and think. It would not surprise me at all if larger parts of their brains are used for communications and reaction to threats of danger, moreso than most mammals. The flight instinct seems instantaneous not pre-thought. And they learn a great deal about communications because they are such social creatures. Most birds in the wild survive by two means - fleeing danger and staying with the flock. It would not shock me at all, then, to see these two aspects of bird brainpower the most highly developed.
BTTT
The most remarkable thing is that they do what they do with a brain that's smaller than a walnut.
I've read stories about Alex and Dr. Pepperberg that literally raise the hair on the back of my neck... the animal is obviously conscious on some level.
Exhibiting behavior that even includes rudimentary moral sense, humor, boredom, anger, jealousy, curiosity.
But let me add Jays are the nastiest. Serious attitude problems.
FReepmail me if you want on or off my health and science ping list.
Heck, throw me on it. Sounds interesting.
Have you heard about Codex Alimentarius? Pretty soon, you won't be able to buy Vitamin C over the counter. I'm not kidding.
Have you heard about Codex Alimentarius? Pretty soon, you won't be able to buy Vitamin C over the counter. I'm not kidding.
I don't see this Senate rolling over for the WTO.
Birds are extremely intelligent, by and large. I'm not surprised the article was illustrated with a picture of a bluejay - they are diabolically clever creatures. (This is why God gave them a four-year lifespan.) My favorite bird is the Northern Mockingbird, mimus polyglottis; not only is it intelligent and a beautiful singer, but it is absolutely fearless in defense of nest and territory -- a fitting characteristic for the state bird of Texas!. I have seen mockingbirds attack and drive off bluejays, grackles, and many other birds larger than themselves, including raptors such as red-tailed hawks. A mockingbird will also dive-bomb dogs, cats, and people if they venture into their territory. ( I was on the receiving end of such a dive-bombing once, receiving a sound whack on the head from Mrs. Mockingbird's wings for my trouble.) They also mate for life and eat garden pests. What's not to like?
We all know that parrots and macaws are intelligent, but less well known is how smart the common crow is. Genus corvus has a reputation as a breed of tool-users, as is pointed out above, and ravens and other blackbirds are also capable of making and using tools.
Owls are smart, but only about as intelligent as cats, and for good reason -- an owl is basically a flying cat: same nocturnal habits, same hunting style, same taste in prey, same social structures. An owl's eyes are structurally similar to a cat's as well, and some species even have external ears like a cat. (The "horns" on a Great Horned Owl are its ears.) Like cats, some raptors can be tamed and trained for hunting or kept as pets, including falcons, hawks, and eagles. (I once laughed at a photo in a magazine of a lady who collected fishheads from fishermen in Alaska just to feed the bald eagles; the sight of this lady on a pier surrounded by a dozen of more bald eagles, each begging for treats and hissing at one another like greedy kittens in line for a squirt of milk, was highly amusing.)
Perhaps not this time around. But all these assaults are like chinese water torture or something. A constant drip, drip, drip can cut a hole in the strongest concrete.
My parakeets Peppy, Perky and Mischief applaud the sentiments in the article. They maintain that avians are superior as a species to humans, who exist only to feed and entertain their avian companions.
Our household includes a couple of Blue Crown Conures and a Sengal, as well as two dogs. One of the dogs, a Sheltie, is extremely smart but the birds, esp. the conures, are something else. They just relate to you on a whole other level. I have no doubt that birds are 'thinking' critters and owning one/ being owned by one is very much, as you say, like raising kids. Incredible creatures.
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