Woodpecker species, inhabiting the rocky and grassy hills of South Africa, and the Andean flicker is another. The Swiss Ornithological Institute has set up a monitoring program to record breeding populations of woodland birds. This has shown that deadwood is an important habitat requirement for the black woodpecker, great spotted woodpecker, middle spotted woodpecker, lesser spotted woodpecker, European green woodpecker and Eurasian three-toed woodpecker. Populations of all these species increased by varying amounts in the period 1990 to 2008. During this period, the amount of deadwood in the forest increased and the range of the white-backed woodpecker enlarged as it extended
English folk music and therefore unworthy of attention. Some authors, however, find these distinctions more difficult to maintain. Although erotic songs became part of the standard fare in folk clubs and among folk rock musicians, relatively few of the more explicit songs have been placed on record. The hornpipe is a style of dance music thought to have taken its name from an English reed instrument by at least the 17th century. In the mid-18th century it changed from 3/2 time to 2/2, assuming its modern character, and probably reaching the height of its popularity as it became a staple of theatrical performances.