The Singing-ground Survey provides an index to the relative size of the woodcock breeding population in North America. It is the most important source of data used to guide federal, state and provincial woodcock programs. As part of their courtship behavior, male woodcock exhibit aerial and vocal displays each evening. They begin by giving calls described as "peents" shortly after sunset. From openings called singing-grounds birds alternately "peent" and make flight songs. New survey participants should become thoroughly familiar with these woodcock sounds before running routes. Visit the Cornell Lab of Ornithology's All About Birds page to hear the song of a male woodcock. You can also visit this YouTube website to see and hear a male woodcock peenting. There is also a recording within the training tool PowerPoint presentation.