If You Were a Pigeon, Would You Have a 3D Odor Map in Your Brain?

Portrait of a Pigeon by Sintwister

This morning was all about flatting. Flatting, for the uninitiated, is blocking out where color will go on a comic book page so that the colorist will be able to concentrate on more important things like the palate. It's pretty mindless work. I usually listen to science podcasts while I do it so that my brain can stay engaged while my hands and eyes do the work. Today's podcast was The Skeptic's Guide to the Universe, and my brain was only half engaged as I navigated a rather tricky drawing of a motel parking lot. But then I heard "pigeons are experts at human facial recognition" and my ears perked up.

I was not too surprised by this since pigeons, like the one in this photo by Sintwister, can do many amazing things. And one of the things that they are very good at is pattern recognition. They would be the perfect employees for jobs like airport x-ray scanner since they would go on looking for the outline of a gun or a knife long after their human counterparts became bored. In fact, a good setup would be a pigeon and a human. The human to look for novel evils, the pigeon to double check that normal evils don't make it though when the human is having a bad day. At one point there was even some thought that they might be good to have along on ocean rescue missions. Pigeons are very talented at spotting things from the air, even small things like a drowning human in a vast sea of whitecaps. Sadly though, many humans don't want to serve alongside pigeons so this plan was scrapped.

Photo from kintired's flckr

The thing that did surprise me on the podcast was a casual reference to pigeons having a great sense of smell which they use for navigation.

What? A good sense of smell? I had been under the impression that most birds have a poor to middling sense of smell, one that certainly wasn't good enough to fly by. So I did a little research.

Pigeons do navigate using landmarks that they spot from the air when they are familiar with an area. So the idea of homing pigeons looking down on the city from above is correct. But apparently they are also building up a 3D map in their brains before they ever leave their roosts for the first time. And they're doing it with smell.

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The theory goes that this smell is based on wind direction. Maybe wind that blows from the west smells like the ocean. And wind from the east smells like the desert. Maybe wind from the north smells like a Russian bakery, for all I know. There's no way to ask the pigeons themselves. But some scientists did a very clever experiment where they blocked one of the nares on each member of a flock of homing pigeons. And the birds did indeed have more trouble getting home. Is smell the only way that these birds create a map, illustrated by the one at the right, in their brain? Probably not. There is also a good deal of evidence that they may use magnetic lines along with visual cues, supplemented by their odor map.

All of which proves that pigeons are much better than me. I can barely tell my left from my right, much less retain any sort of map in my head. Bird brained indeed!