Woodpeckers and Weather
North American folklore says that woodpeckers predict the severity of the coming winter and that woodpeckers disappear in anticipation of extreme cold. A pervasive belief found in Europe is that the pecking is a sign of rain on the horizon, perhaps because the loud pecking of some species can resemble a distant thunder roll. In this regard, it is interesting that the woodpecker is the bird of the redheaded Norse god Thor, who wields the hammer and lightning bolt. More obscurely, the woodpecker is said to lead an observer to treasure. I have found that birds who bring rain are very often considered treasure birds.
The treasure the woodpecker is most thrillingly believed to lead to is the springwort. The springwort is a reddish root believed to draw down lightning. It can open any closed or locked door. To find the springwort magicians would seal the entrance to a woodpecker nest. The woodpecker would then fly off to find a springwort, but would be induced to drop the plant when he returned and found that the seal had been removed. The springwort sounds like a very valuable herb, but nobody really knows what a springwort is. Jacob Grimm identified it as the Caper Spurge or Euphorbia Lathyris.