Arizona Yodeler - DeZurik Sisters

Born and raised on a farm in Royalton, Minnesota, Mary Jane (February 1, 1917–1981) and Carolyn Dezurik (December 24, 1918 – March 16, 2009) were part of a family of seven. Their father Joe played fiddle, their sisters sang, and their brother Jerry played accordion and guitar. Inspired by their family and the sounds of the animals and birds around them, they developed an astonishing repertoire of high, haunting yodels and yips that soon had them winning talent contests all over central Minnesota. In 1936, they signed a contract to appear regularly on Chicago radio station WLS-AM's National Barn Dance, and were hired in 1937 to perform on Purina Mills' Checkerboard Time radio show, where they sang as The Cackle Sisters.

http://en.wikipedia.org/wiki/The_DeZurik_Sisters