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The mystery of homing pigeons
How do pigeons know the location of their nest?
No matter how far away you take homing pigeons, as soon as you release them they fly back home without a moment’s hesitation. But how?
This mystery has puzzled mankind since ancient times.
Everyday, we use a range of electronic gadgets, TVs, computers, refrigerators, microwave ovens, mobile phones, etc. But how many of us can explain how they function, or the principles behind them? Many parents have heard questions from their curious and eager kids like “Dad, how does the TV work?” In most cases, daddy will probably mumble something like “I’m sure there are experts who could explain it,” and then desperately try to change the topic.
In the case of man-made tools and machines, there usually really are people who fully understand their mechanisms and can explain them. But there are also cases where nobody fully understands how they work, but we still use them because they are practical.
Homing pigeons (or “carrier pigeons”) are one example. No matter how far from their nest you release them, they always fly straight back home, and people have utilized this feature of pigeons since ancient times to carry messages. In times of war, they have even been used for military purposes, and these days “pigeon races” are popular.
But how do the pigeons know the location of their nest?
Through the ages, a number of different theories have been proposed to solve that riddle. Here are just a few of them.
The route memory theory
This is the idea that the pigeons remember the whole itinerary as they are transported far away from their nests. This, however, is refuted by the fact that they can find their way home even when they are transported under anesthesia.
The landmark theory
Here, the idea is that the pigeons remember local landmarks near their nests. This might work up to a few kilometers, but hardly over distances of several hundred kilometers, so this theory is also ruled out.
The solar compass theory
This theory claims that pigeons know the direction from the position of the sun. However, pigeons can fly home in cloudy weather and at night as well, so this theory doesn’t hold either.
The magnetic compass theory
According to this theory, pigeons can detect the earth’s magnetic field to determine the direction. In fact, experiments have been made that show that if you attach magnets to the pigeons when you release them, their sense of direction is weakened. There have also been reports about organs found in pigeons’ bodies that reputedly are related to geomagnetism.
For the moment, the theory that they use geomagnetism is the most promising, but it is by no means as if the mechanism has been revealed in any close detail. Maybe the system involves a combination of other factors, or perhaps a totally different option remains to be discovered.
