Progress comes slowly on the question "Why does the chicken cross the road?" But come it does. The answers (for there seem to be many) strut in jerkily from different directions. A new study explains that magnetic fields play some sort of role, at least sometimes, in chickens' decisions to navigate hither or yon.
The study has a title that seems swiped from a children's book: The Magnetic Compass of Domestic Chickens, Gallus Gallus. Published in the Journal of Experimental Biology, a publication that generally does not cater to youngsters, it adds flesh and feathers to the sketchy picture revealed in an earlier report called Chickens Orient Using a Magnetic Compass.
Many cultures wonder about the chicken navigation mystery. And so, fittingly, the "magnetic compass" research team is international. Its members - Wolfgang Wiltschko, Rafael Freire, Ursula Munro, Thorsten Ritz, Lesley Rogers, Peter Thalau and Roswitha Wiltschko - work, variously, in Germany, at JW Goethe-Universitat Frankfurt; in Australia at the University of New England in Armidale and at the University of Technology Sydney; and in the US, at the University of California, Irvine.
They did their experiments in Australia, with Australian chickens. The chickens had to track down a red ball that had been shown to them and then moved. The scientists generated a magnetic field which, they hoped, would monkey with the chickens' orientation. The chickens, in their quest for the red ball, acted as if under the influence of a monkeyed-with magnetic field.
Thus the scientists' conclusion: magnetic fields matter to chickens. This presumably is true of chickens elsewhere, although the report is not explicit on the point.
What do magnetic fields do for the chicken? They "facilitate orientation within the home range", say the researchers. In more specific terms: "Tests in magnetic fields with different intensities revealed a functional window around the intensity of the local geomagnetic field, with this window extending further towards lower than higher intensities."
What the report hints is that chickens don't seem to rely heavily on magnetism. Are the chickens capable of more? Has our civilisation withered their reliance on the earth's magnetosphere? The report is mum on these questions.
The basic question of why a chicken crosses a road stands, at best, partially answered. Perhaps the most likely to solve it is Professor Ian JH Duncan, formerly of Edinburgh, and now chair in animal welfare at the department of animal and poultry science at the University of Guelph, in Canada.
In 1986, Duncan and a colleague presented a paper at the winter meeting of the Society for Veterinary Ethology, in London. The title: Some Investigations Into Motivation in the Domestic Fowl.
Duncan appears to be methodically delving into the fowl's motivation. In 2000 he co-authored Working for a Dustbath: Are Hens Increasing Pleasure Rather Than Reducing Suffering? Pullet-road-crossing enthusiasts can hope that one day Duncan will confront, directly, the question of questions.
(Thanks to Richard Wassersug for bringing the pullet magnetism study to my attention.)
· Marc Abrahams is editor of the bimonthly magazine Annals of Improbably Research and organiser of the Ig Nobel Prize