A Sting in the Tale by Dave Goulson Page A

be rather annoyed and have no idea which way to go. You would of course ring the police, or ask someone for directions, but suppose you were unable to do either? Would you ever get home? Contrast this with the pigeon’s response. With barely a moment’s hesitation, the pigeon sets off flying at a brisk pace in precisely the correct direction. A few hours later it is happily perched in its loft tucking into a tasty bowl of grain. How on earth does it do this? Despite our vastly superior intellect and many years of scientific research, we have still not fully understood how pigeons navigate home so expertly from places that they have never previously visited. They can certainly use the sun or the stars as a compass, and can even tell where the sun is on heavily overcast days by their ability to detect the plane of polarised light penetrating the clouds. There is also some evidence that they have miniature magnets in their brains that enable them to detect the earth’s magnetic field, so they have at least three inbuilt compasses. Impressive though all this is, you need more than a compass or three to find your way home if you have no idea which direction home is. And therein lies the mystery. It is almost as if they have a seventh sense (the sixth being the ability to detect magnetic fields) that we have yet to discover – a miniature GPS system perhaps, which tells them exactly where they are in relation to home.
    At university I once had to write an essay on homing in pigeons, and became intrigued. In my later life as a university lecturer in the late 1990s, I couldn’t resist investigating the navigation abilities of bumblebees. My experiments were very simple, and followed the model used by pigeon fanciers the world over. I set up five buff-tailed bumblebee nests in boxes in my garden. At that stage I was living in Southampton, at almost the opposite end of the country from my current home in Scotland. We had there a very dilapidated, ivy-encrusted structure that might once have been described as a gazebo, in which I placed the row of nests on a bench seat. This I called my ‘bumblebee loft’. When I first opened the doors to the newly installed bumblebee nests, the bees poured out, eager to explore their new environment. The air filled with hovering, circling bees, but within a few minutes they had all disappeared off into the surrounding gardens where they happily began foraging, returning a little later with balls of pollen on their legs and full honey stomachs. Once the bees were experienced, which took some only an hour or two, their behaviour on leaving the nest became obviously different; instead of indecisively hovering about or circling the nest, they whizzed out purposefully and disappeared at high speed.
    When the bees had had a week to settle down, I began my homing trials. I caught them as they left their nest to forage and glued a tiny coloured and numbered disc to each of their backs so that I could recognise them again. I then placed them individually in small cylindrical cardboard pots (still known to entomologists as pillboxes, from their original use) and drove them in my car to a random location. At the time I had a rather silly two-seater Toyota MR2 sports car and the stack of cardboard pillboxes would sit on the seat next to me as I roared through the Hampshire countryside. At a random location, predetermined by blindly sticking a pin in a map, I would stop by the roadside and release a batch of ten bees, noting down their numbers. Invariably and understandably they looked rather confused, and would usually circle about in much the same way as they had when they first left their nest in my bumblebee loft. Some would head straight to the nearest flowers for a quick drink after the hot journey in the car. Within a few minutes, all had disappeared into the distance. At this point I would jump back into the car and race for home. Once back at the loft I would sit and wait for the