Posted on 02/04/2004 6:21:47 PM PST by blam
How do homing pigeons navigate? They follow roads
By Caroline Davies
(Filed: 05/02/2004)
Researchers have cracked the puzzle of how pigeons find their way home: they just follow the main roads.
Zoologists now believe the phrase "as the crow flies" no longer means the shortest most direct route between two points. They say it is likely that crows and other diurnal birds also choose AA-suggested routes, even though it makes their journeys longer.
Some pigeons stick so rigidly to the roads that they even fly round roundabouts before choosing the exit to lead them back to their lofts.
Animal behaviouralists at Oxford University are stunned by their findings, which follow 10 years of research into homing pigeons. For the last 18 months they have used the latest global-positioning technology, allowing them to track the ground the birds covered to within one to four metres.
"It really has knocked our research team sideways to find that after a decade-long international study, pigeons appear to ignore their inbuilt directional instincts and follow the road system," said Prof Tim Guilford, reader in animal behaviour at Oxford University's Department of Zoology.
"For long-distance navigation and for birds doing a journey for the first time, they will use their inbuilt compasses and take sun and star bearings.
"But once homing pigeons have flown a journey more than once, they home in on a habitual route home, much as we do when we are driving or walking home from work.
"In short, it looks like it is mentally easier for a bird to fly down a road and then turn right. They are just making their journey as simple as possible".
His team carried out dozens of tests with pigeons in Oxfordshire, releasing them between 10 and 20 miles from their lofts, each with a tiny GPS tracking device attached to their backs. Matching their routes, they found most flew straight down the A34 Oxford bypass.
"It was almost comical watching one group of birds that we released near a major A road. They followed the road to the first junction where they all turned right, and a couple of junctions on, they all turned left".
Not all of the pigeons did it all of the time, but there were enough occasions when they did for the researchers to build up a pattern.
"We even had one bird flying down the road, going round the roundabout, taking one of the turnings down that to another roundabout then leaving the road.
"Up until now, we have always thought about the way that birds go in terms of the energetics of the flight efficiency, which is the most direct route home . . . as in the phrase 'as the crow flies'.
"But the answer is, they don't go as the crow flies, and neither, it is my hunch, do crows. As they get familiar with the environment, they just follow the obvious features which often don't take them directly home.
"That may sound trivial to some people, but to us that is quite important because it is starting to get at the structure of a birds' memories, and what the map looks like to a bird.
"We are genuinely surprised. It makes you think what did pigeons and other birds do before we cluttered the landscape with all these linear features. And it makes you think hard about how flexible animals are amid what we have done to their landscape.
"Lots of animals have invaded and made use of the changes we have provided for them. You only have to look at Trafalgar Square and how it has become a fantastic three-dimensional cliff environment for pigeons to live in. It's evolution in action.
"Maybe they were using rivers and coastlines before. But when we got our first tracks of birds flying up the dual carriageway and then turning off the road to the village where their home loft was, we thought, 'This shouldn't happen, but it's very exciting'.
"Roads and important things like roundabouts do appear to be very attractive to birds. If they have made the journey before, the pigeons are more likely to say, 'Well, I know this is south - the way I want to be going - but rather than fiddle around with my inbuilt compass I'm going to follow the A34, which will take me home nicely'."
Peter Brian, general manager of the Royal Pigeon Racing Association, based in Cheltenham, said: "Every Saturday you can see whole flocks of pigeons flying up the M5. Prof Guilford's research in animal behaviour and migration is renowned and there is a lot of credence to what he is saying. I think his findings are spot-on".
But they said they released the birds some distance away from their loft and then tracked their journey back. So the birds must have been driven to the release point... along that road!
Is it possible the birds were driven along that road, and they somehow have a way to simply retrace their route? Some sort of geographic memory system, maybe?
Interesting. I hadn't considered that.
Sounds like they're better drivers than some of the people I see out there!
Took the bus?
Well when their clock had been reset they were provided a star field on the bowl above their head. As the birds tried to jump for liftoff their tracks were recorded on carbon paper on the sides of the bowl. It was evident that their attempts to migrate were influenced by the star field, (and their gonads!!!)
Maybe they stop at road houses along the way but......
I know this post will get many of you freepers hot and bothered but if your gonads grow to 5% of your body weight don't say I didn't warn you heh! heh!
A good object lesson. Remember kids, NEVER let your b**** overload your brains.
That's a good question - have to check their methods. If they were like anything I saw in school, the cages were covered while they traveled and they used different routes to the release points.
Some animals have been shown to use visual cues in internal map making. I remember reading one study of squirrels and nut caching. The researchers modeled a cage with a couple trees, rocks, bushes etc and watched where the squirrels cached their nuts. Then they moved everything a meter to the left and watched where the squirrels went to retrieve the nuts when let back in the cage - all the squirrels were a meter off.
So probably the pigeons are using visual aids in their "maps" and you can't get much more visual than looking down and seeing really big lines on the ground.
Notice on the map that the pigeon appears to have taken the wrong left, backtracked, and then took the next left.
Wow. Who woulda thunk it?
I Fly Roads.
My guess - they followed rivers and streams, treelines and ridges, essentially other visual clues.
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