Yellow Warbler, female in the eastern Sierra Nevada Mtns. at 8200 feet. The most widespread breeding warbler in North America. There are 3 species, or groups of Yellow Warbler, and 43 subspecies. The east slope of the Sierra Nevada Mtns., including the Mono Basin and the cascading streams that feed Mono Lake hold the largest breeding population of the Yellow Warbler in california. This is a highly migratory warbler.