Wednesday, May 27, 2009

Animal minds: Rooks in captivity show more feats using tools

In "Tool-making Birds: Necessity Is The Mother Of Invention For Clever Rooks" (ScienceDaily, May 26, 2009), we learn that
Researchers at the Universities of Cambridge and Queen Mary, University of London have found that rooks, a member of the crow family, are capable of using and making tools, modifying them to make them work and using two tools in a sequence.
The interesting thing is that rooks have not been observed to use tools in the wild.

Rooks are, as anyone who has dealt with them knows, unusually intelligent birds, rivalling chimpanzees in tool use. As one researcher noted,
“Rooks have been shown to rival chimpanzees in physical tasks, leading us to question our understanding of the evolution of intelligence.”
Which is all the more interesting because they have smaller brains than mammals, and lack the parts associated with mammal intelligence:
The brain of a bird weighs about 10 times as much as a brain of a reptile of the same weight, but slightly less than that of a mammal of the same weight. However, there is considerable variation between birds of similar size. For birds weighing in at around 85g, brain weight varies from 0.73g for a Quail to 2.7g for a Great Spotted Woodpecker. There is therefore quite a range in the intelligence of birds, with game birds at the bottom of the list and Woodpeckers, Owls and Parrots at the top.

A bird's brain is different to a mammalian brain in that the complex folds found in the cerebral cortex of mammals are missing and the cerebral cortex itself is much smaller proportionally than in mammals. Instead the corpora striata, a more basic part of the cerebral hemispheres is proportionally larger and better developed. It is this portion of a bird's brain which is used to control instinctive behaviour - feeding, flying, reproduction etc. The mid-brain is also well developed as this is the part of the brain primarily concerned with sight, while the olfactory lobes are reduced as would be expected given that bird's in general have little use of the sense of smell.

The bird's skull is mostly occupied by eyes and the brain has to make do with what space it can find in a rather narrow cranium. - The Earthlife Web
The main thing to see here is that some birds, like some mammals, are very intelligent but others are not. There is no Tree of Intelligence that puts mammals above birds in principle.

Why is this level of ingenuity so rarely displayed in the wild? Researchers construct elaborate tests, which some birds pass. But birds like rooks probably only solve problems when necessary. In nature, most problems are solved more simply. For example, if food seems unusually hard to extricate, the clever bird is likely to resolve the problem just by flying on to an easier source. By contrast, in a cage in a laboratory, the bird lacks that option, and must display any ingenuity it possesses.

Coffee!: Crow drinking Stella Artois

For heaven's sake, someone, fetch that crow a glass.

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