Systematics

Three races (L. g. griseus; hendersoni; caurinus) with distinct breeding areas and migration routes, separable by plumage and size (See Distinguishing characteristics and Distribution, above, for details).

Genus consists of 3 species, 2 of which, L. griseus and L. scolopaceus, were formerly considered conspecific (see Pitelka 1950). Protein distance is small (D = 0.060) but of magnitude similar to some other closely related species (Avise and Zink 1988). A third species, Asian Dowitcher (L. semipalmatus, sometimes called “Snipe-billed Godwit” and placed in monotypic genus, Pseudoscolopax; Sutton 1949) breeds in Asia.

Possible relationships of Limnodromus to other shorebirds are unresolved, in part because of similarities between Asian Dowitcher and godwits (Limosa; cf. Lowe 1931, Pitelka 1948, Sutton 1949, Rand 1950, Kozlova 1962). Downy plumage characteristics indicate ties to the snipe (Jehl 1968b), and that resemblance to godwits is convergent. On the other hand, morphological studies indicate ties to the calidridine sandpipers and godwits (Chu 1995). DNA hybridization studies (Sibley and Ahlquist 1990) did not specifically treat this subject. Thigh musculature studied by Fleming (1966). Placed in own tribe, Limnodromini, by Am. Ornithol. Union (1998).

Mitochondrial DNA suggested Short-billed Dowitcher is closely related to Red Knot, but comparisons few and several relevant taxa (e.g., L. scolopaceus, Gallinago sp., or Limosa sp.; Dittman and Zink 1991) not examined. Genetic evidence indicates divergence of Short-billed and Long-billed dowitchers about 4 Ma (Avise and Zink 1988). Random amplified polymorphic DNA allows differentiation of Short-billed and Long-billed dowitchers (Haig et al. 1997). Allozyme analysis of samples from Texas and Alaska, presumably including at least 2 races, characterized the Short-billed Dowitcher as a panmictic population (Baker and Strauch 1988).