Most worm charming methods involve vibrating the soil, which encourages the worms to the surface. In 2008 researchers from Vanderbilt University demonstrated that the worms surface because the vibrations are similar to those produced by digging moles, which prey on earthworms. The same technique is used by many species of bird, who devour the worms as they appear above ground.
The activity is known by several different names and the apparatus and techniques vary significantly. "Worm grunting" generally refers to the use of a "stob", a wooden stake that is driven into the ground, and a "rooping iron" which is used to rub the stob. "Worm fiddling" also uses a wooden stake but utilises a dulled saw which is dragged along its top.
Techniques vary from sprinkling the turf with water, tea and beer to acupuncture, music or just "twanging" with a garden fork.In some organized competitions, detergents and mechanical diggers have been banned.
Worms are most commonly found in damp or wet conditions and tend to move away from dry soil. The success of worm charming can often depend on these soil conditions, with charmers choosing damp locations or using water to attract the worms.
Worm charming as a profession
Worms are sold as a live bait for fishermen and many sellers use worm charming techniques to gather their stock. In some locations professional worm grunters need to obtain a permit in order to ply their trade.
Competitive worm charming
In most competitions the fiddlers with the collector (or collectors) of the most worms in a set time being declared as the winners. They usually have a zone in which to perform their charming, measuring three yards square.
One of the first worm charming events took place in a school fête at Willaston County Primary School in Willaston, Cheshire. The "World Worm Charming Championship" started in 1980 and is now an annual event that celebrates the sport. It was organised by then-headmaster John Bailey, who wrote the original rules for the competition.
The current world record was established on June 29, 2009 by 10-year-old Sophie Smith of Willaston, England who raised 567 worms during Britain's World Worm Charming Championship.
Rules of the The British and European Federation of Wormcharmers include a plot no greater than 3 ft by 4 ft, a five-minute warm up period, a three-person team of charmer, catcher and counter and that all worms must be returned to the ground after the contest (according to the British Association of Worm Length Supporters (BAWLS).