Placing avian brain in new light, bird behaviour may be seen as an adaptation to solve socio-ecological problems similar to mammals
Here is a remarkable incident. For over three weeks in June 2007, a small mockingbird kept on harassing a particular post-woman in South Gary Place, Tulsa, Oklahoma, USA. Rather unusual, since while dogs are famous for bothering postmen and women, a bird, that too the tiny little mockingbird, recognised and went after this post-woman!
That recognition of particular persons is not unusual is borne out by a recent scientific experiment. Mockingbirds living in cities quickly learn to identify individual humans; this is the title of a paper published by a group of Florida researchers, led by Dr. Douglas J. Levey
The experiment involved the same human approaching and threatening the nest of a mockingbird in the university campus on four successive days. The mockingbirds raised alarm, rushed to attack her and rushed towards her each day, at increasingly greater distances from her. But when a different human came near the nest on the 5th day, the birds reacted as they did on the first day with the first intruder.
And they were quite comfortable with the hundreds of people walking across the campus quadrangle near the nest, as long as they were safely away.
These results suggest that the typical urban bird, the mockingbird, learns quickly to identify individual humans; two 30-second exposures of humans at the nest suffices (you may download and read the paper and see how easy and clever the experiment was; access www.pnas.org/content/early/recent and go to May 18th.
The authors draw a general conclusion from this. “Urban birds enjoy generally high nesting success, even though urban environments are characterised by large populations of nest predators.
We suggest that mockingbird’s perceptive ability and rapid learning predispose them to success in novel environments.” In other words, birds are smarter than we have given them credit for so far.
Dr. Nathan J. Emery of the University of Cambridge has been researching on the intelligence of birds, a field that he calls “cognitive ornithology: the evolution of avian intelligence” (Phil.Trans. R. Soc. B.2006, 361, 23-43; this paper too is freely accessible). It is not just mockingbirds that we should be impressed with. He points out that birds are exceptionally skilled at discriminating between visual images.
Pigeons can discriminate between images of aerial photographs, people, trees and water, chairs, cars, humans, flowers, and of course other pigeons. One Dr. Watanabe claims that pigeons could tell apart the paintings of Picasso, Monet, Chagall and van Gogh!
And the African grey parrot named Alex, famous among scientists (and who recently died) could vocally tell apart over 100 objects of different colours, shapes and materials. Dr. Irene M. Pepperberg of the University of Arizona, who studied Alex in detail, wrote an entire book in 1999, titled ‘The Alex studies: cognitive and communicative ability of Grey parrots’ (Harvard University Press).
While most studies on avian intelligence have been done on pigeons, parrots, chicken and quails, special attention has justifiably been given to crows and parrots. The reason is the surprising fact that their forebrains are relatively the same size as those of monkeys and great apes!
Emery points out that this fact “places avian forebrain in a new light, where bird behaviour may be explained as an adaptation to solving socio-ecological problems similar to mammals. Their hardware is different from that of mammals, although evolved from the same structure”.
Pepperberg has said that if mammalian brains are like IBM PCs, bird brains are like Apple Macintoshes, the wiring and processing are different but the resulting output (i.e. behaviour) is similar.
The key point
The key point is not to look at just the brain size, but the more relevant ratio of brain size to body size (or the brain- body ratio).
It is this ratio that makes us understand, for example, why a little mouse can be almost as smart as us, or why it is said that a chimpanzee is as intelligent as a six-year-old human.
Of course, the regions within the brain are important, just as the components within the hardware in the computer are. This is how differences between species occur, for example, between songbirds, and between crows on the one hand and quail and pheasant on the other.
The emerging moral
Ironically, a moral emerging out of these studies is to call someone ‘bird-brained’ is no longer an insult, but praise. That crows practise ‘folk physics’ and make tools, just as chimps do, exemplifies this. Crows are known to use hooked twigs to poke out insect larvae from tree holes.
One, called Betty, studied by Oxford University scientists, was even able to fabricate a hooked wire and pick up a piece of meat from the bottom of a tall glass cylinder (see movie at www.care2.com/news/member/224269678/892566 ). Next time you read Panchatantra, Jataka tales or Aesop’s fables, you will appreciate how fiction and fact are close.D. BALASUBRAMANIAN