This inhabitant of thick, tangled vegetation (particularly in wet areas) is one of North America's most widespread warblers, breeding throughout the continental United States (including part of Alaska) and in parts of all Canadian provinces. The male's distinctive black mask and wich-i-ty wich-i-ty wich-i-ty song make it an easily identified warbler. First collected in what is now Maryland, and described by Carl von Linné (Linnaeus) in 1766, the Common Yellowthroat was one of the earliest species of birds tobe described from the New World.
This species exhibits a wide range of geographic variation in plumage and taxonomists have described many subspecies in their struggle to categorize this variation. It is a migrant through much of its range, although some populations are partially migratory or sedentary. Two sedentary populations, the San Francisco or Salt Marsh Yellowthroat and the Brownsville Yellowthroat (G. t. sinuosa and G. t. insperata), have undergone severe declines in this century because of habitat loss and alteration. Despite the widespread occurrence and abundance of yellowthroats, few studies (none of which are long-term) of the breeding biology or behavior of this species have been conducted. Two detailed studies of breeding behavior have been published for populations in Minnesota ( Hofslund 1959 ) and Michigan ( Stewart 1953 , Hofslund 1959 ). Only song and singing behavior have received recent attention in the literature (e.g., Kowalski 1983a , Ritchison Ritchison 1991 , Ritchison 1995 ), although recent theses have dealt specifically with the yellowthroat and habitat use ( Foster 1977 , Hsu 1993 , Klicka 1994 ), song and signaling ( Chen 1993 , Hsu 1993 , Klicka 1994 ), breeding activity ( Foster 1977 , Klicka 1994 ), and population status of sedentary populations ( Foster 1977 , Klicka 1994 ). Systematic studies have also been conducted, both of the genus (Escalante-Pliego Escalante-Pliego 1978 , Escalante-Pliego 1991 ) and within the species ( Zink and Klicka 1990 ).