Systematics

Family Scolopacidae, subfamily Scolopacinae, tribe Limnodromini (Am. Ornithol. Union 1998). Originally named Limosa scolopacea by T. Say in 1823 (Am. Ornithol. Union 1998) and later placed in genus Macrorhamphus (Howe 1901). Regarded as subspecies of Short-billed Dowitcher for much of this century (Howe 1901, Ridgway 1919, Peters 1934). Systematics of Long-billed Dowitcher and congeneric Short-billed Dowitcher have been debated for more than a century.

Monotypic; no significant variation noted.

The genus Limnodromus, dowitchers, includes 3 species: Asian, Short-billed, and Long-billed dowitchers (Sibley and Monroe 1990). Ecological and morphological distinctness of Long-billed and Short-billed established by Pitelka (1950), after which these 2 dowitchers were considered separate species and as allospecies of a superspecies group (e.g., Mayr and Short 1970). Recent genetic analyses support separation of these species. Fixed differences in 24 mtDNA restriction sites and 14 fragment profiles of Long-billed and Short-billed dowitchers indicated that, for congeners, the species are near the high end of the scale of divergence (Avise and Zink 1988). Similarly, a high number of loci separated these dowitchers in random amplified polymorphic DNA testing (Haig et al. 1997). Pitelka (1950) suggested that Long-billed Dowitcher may have separated from Short-billed during glacial periods in Beringia as Long-billed nested to the north and west of glaciated areas and Short-billed remained south; if mtDNA has evolved in dowitchers at a similar rate as other vertebrates, however, genetic divergence indicates separation may have been as long as 4 million yr ago (Avise and Zink 1988). Asian Dowitcher doubted as a close relative by external characteristics (Pitelka 1948), but grouping with other dowitchers later supported by Rand (1950). Dowitchers appear to be closely related to godwits and calidridine sandpipers (Sibley and Ahlquist 1990, Chu 1995).