Naturalized nonnative bird species are generally increasing in diversity and abundance in human-modified habitats of North America (Johnston and Garrett 1994, Garrett 1998a). Some of the more recently established species present field identification challenges because they are unfamiliar to many birders and because they may superficially resemble certain native species (Garrett 1998b ). This situation is improving with the recent portrayal of many new naturalized taxa in commonly used field guides (National Geographic Society 1999), but considerable potential for confusion remains.