We had a question sent in to us from someone who wondered why seagulls would venture into his garden stamping their feet in turn on his lawn that looked a little like dancing.
Gulls perform this dance to bait worms. During heavy rain earthworms will instinctively rise to the surface and it used to be thought that this was so they don’t drown in their underground burrows. However, new research suggests that this is not true as worms actually breathe through their skin and require moisture in the soil to do so.
It is now understood that worms come to the surface to migrate and moist soil means they can move further distances than if the ground is dry.
By stamping their feet on the ground, gulls produce vibrations that mimic the sound of raindrops. Worms will then come to the surface and the gulls can then be observed scrutinizing the ground in search of their next meal. During the rain dance you will see them pause and move their heads from side to side to help them get a closer view.
Nikolaas Tinbergen, a Dutch ornithologist, who won the 1973 Nobel Prize in Physiology or Medicine along with Karl von Frisch and Konrad Lorenz for their “discoveries concerning organization and elicitation of individual and social behaviour patterns”, put forward the idea that the dance is learned behaviour with older gulls teaching younger gulls the movements.
Environmental factors also influence the behaviour as it is more often seen in birds that have to supplement their diet or who have moved inland from the coast.
Worm charming can also be observed in other birds such as thrushes, blackbirds and robins, and animals such as wood turtles.