NATURAL selection is a harsh interrogator at the best of times. But if you are a bird, it has an extra question, not asked so forcefully of animals that cannot fly: “is that extra gram of weight really necessary?” Contrary to the insult “bird-brained”, birds are not notably more stupid than mammals, but the pressure to keep organs light applies to the cerebrum as much as it does to anything else.
For the past century, though, birds have faced a new enemy that might require them to get smarter: the motor car. These days, cars and other motorised vehicles kill around 250m birds a year. That sounds like a significant selective pressure, so Anders Moller, an evolutionary biologist at the University of Paris-Sud, in France, decided to find out whether it really was.
Dr Moller’s hypothesis was that avoiding vehicles needs intelligence, and intelligence needs a big brain. The conclusion of this syllogism is that small-brained birds are more likely to be road-kill than large-brained birds are. To test this idea, though, he needed data on a lot of dead birds.
That serendipity plays a part...Continue reading
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