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Worm baiting
The last word– WORM BAITING While sitting on a bench beside a local green, I noticed a gull performing an excellent version of Riverdance. Then it stopped and scrutinised the grass around its feet. This sequence was repeated for about 15 minutes. I assume the gull was trying to attract worms to the surface with its rhythmic dance. Was it? If so, how does the strategy work?
● Yes, like many species of birds, some gulls have learned the earthworm-raising trick. Earthworms stay underground during the day unless flooded out by rainwater or alarmed by ground vibrations that suggest the approach of a mole. Just jab a garden fork into earth well populated with earthworms and some will pop out to avoid the little creature in black velvet. Different birds have different techniques. Blacksmith plovers, rather than hunting earthworms, flush out
technique was faulty, with long, loping leaps instead of jerky thumps, so it did not scare enough worms and soon gave up. Or maybe it just didn’t like the flavour of those earthworms it had caught. Jon Richfield Somerset West, South Africa ● The gull was indeed trying to get worms to surface. Underground, the rhythm of the gull’s feet sounds much like rain. Earthworms like to surface during rain because it enables them to move around overground without drying out – this is impossible when it is dry. By tricking the earthworms, the gulls get an easy meal. The gulls may have learned this trick from watching other gulls, or they have inherited the behaviour. Laura Still Devon, UK
“It appears the gull was applying successful food-gathering behaviour that evolved in one environment to another” at the time. I always read The Last Word first, so, moments later, when I opened the back cover and read the question about worm baiting I was, to say the least, rather surprised. It appears that the gull seen by the questioner was applying successful food-gathering behaviour that
evolved in one environment to another. This does make sense when one considers that gulls originate not in marine environments, as is frequently supposed, but in moorland ones. Presumably the behaviour evolved in environments that contained bogs, where the puddling behaviour would work successfully in damp ground some way from the water’s edge. The vital question, though, is whether the gull was successful in drawing up worms, or anything else edible, to the surface. Graham Houghton Aldgate, South Australia
THIS WEEK’S QUESTIONS Blow hole What is the purpose of the small hole halfway down the outside shell of a Bic ballpoint pen? Frank Horseman Derby, UK It’s no yolk At breakfast one day, my 4-year-old son was peeling his boiled egg when he noticed something unusual. On the side of the egg was an almost perfect white square with sides about 1 centimetre long. This was enclosed in an oval patch of yellow matter (see photo, left). Although the yellow patch looked like egg yolk, the egg appeared normal when I cut it in half, and I could not see any connection between the egg yolk in the centre and the yellow patch on the outside. Does anyone know how this formation was created? Johan Forsberg Linköping, Sweden
“Just jab a garden fork into earth well populated with earthworms and some will pop out to avoid moles” grasshoppers, caterpillars and moths by tickling short grass with a trembling foot held forward. Gulls that have learned the trick stamp for earthworms. Similarly, I have seen thrushes stamp by hopping hard with stiff legs. Once I was startled to see a red-winged starling watching an olive thrush’s technique attentively, then having a go itself. It did get a worm or two, but its Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format.
● I was sitting on Henley Beach in South Australia recently, watching a gull “puddling” the sand at the water’s edge before inspecting the water for any food items it might have disturbed. It seemed to be doing quite well for itself. By an amazing coincidence, I had a copy of New Scientist in my hand
New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address.
Last Words past and present, plus questions, at www.last-word.com
● Yes, like many species of birds, some gulls have learned the earthworm-raising trick. Earthworms stay underground during the day unless flooded out by rainwater or alarmed by ground vibrations that suggest the approach of a mole. Just jab a garden fork into earth well populated with earthworms and some will pop out to avoid the little creature in black velvet. Different birds have different techniques. Blacksmith plovers, rather than hunting earthworms, flush out
technique was faulty, with long, loping leaps instead of jerky thumps, so it did not scare enough worms and soon gave up. Or maybe it just didn’t like the flavour of those earthworms it had caught. Jon Richfield Somerset West, South Africa ● The gull was indeed trying to get worms to surface. Underground, the rhythm of the gull’s feet sounds much like rain. Earthworms like to surface during rain because it enables them to move around overground without drying out – this is impossible when it is dry. By tricking the earthworms, the gulls get an easy meal. The gulls may have learned this trick from watching other gulls, or they have inherited the behaviour. Laura Still Devon, UK
“It appears the gull was applying successful food-gathering behaviour that evolved in one environment to another” at the time. I always read The Last Word first, so, moments later, when I opened the back cover and read the question about worm baiting I was, to say the least, rather surprised. It appears that the gull seen by the questioner was applying successful food-gathering behaviour that
evolved in one environment to another. This does make sense when one considers that gulls originate not in marine environments, as is frequently supposed, but in moorland ones. Presumably the behaviour evolved in environments that contained bogs, where the puddling behaviour would work successfully in damp ground some way from the water’s edge. The vital question, though, is whether the gull was successful in drawing up worms, or anything else edible, to the surface. Graham Houghton Aldgate, South Australia
THIS WEEK’S QUESTIONS Blow hole What is the purpose of the small hole halfway down the outside shell of a Bic ballpoint pen? Frank Horseman Derby, UK It’s no yolk At breakfast one day, my 4-year-old son was peeling his boiled egg when he noticed something unusual. On the side of the egg was an almost perfect white square with sides about 1 centimetre long. This was enclosed in an oval patch of yellow matter (see photo, left). Although the yellow patch looked like egg yolk, the egg appeared normal when I cut it in half, and I could not see any connection between the egg yolk in the centre and the yellow patch on the outside. Does anyone know how this formation was created? Johan Forsberg Linköping, Sweden
“Just jab a garden fork into earth well populated with earthworms and some will pop out to avoid moles” grasshoppers, caterpillars and moths by tickling short grass with a trembling foot held forward. Gulls that have learned the trick stamp for earthworms. Similarly, I have seen thrushes stamp by hopping hard with stiff legs. Once I was startled to see a red-winged starling watching an olive thrush’s technique attentively, then having a go itself. It did get a worm or two, but its Questions and answers should be concise. We reserve the right to edit items for clarity and style. Include a daytime telephone number and email address if you have one. Restrict questions to scientific enquiries about everyday phenomena. The writers of published answers will receive a cheque for £25 (or US$ equivalent). Reed Business Information Ltd reserves all rights to reuse question and answer material submitted by readers in any medium or format.
● I was sitting on Henley Beach in South Australia recently, watching a gull “puddling” the sand at the water’s edge before inspecting the water for any food items it might have disturbed. It seemed to be doing quite well for itself. By an amazing coincidence, I had a copy of New Scientist in my hand
New Scientist retains total editorial control over the content of The Last Word. Send questions and answers to The Last Word, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, UK, by email to [email protected] or visit www.last-word.com (please include a postal address in order to receive payment for answers). For a list of all unanswered questions send an SAE to LWQlist at the above address.
Last Words past and present, plus questions, at www.last-word.com