Systematics

Figure 2. Distribution of Mourning Dove subspecies in N. America

Geographic Variation

Three geographic trends in morphological variation on North American continent (Aldrich 1993, Appendix 1): (1) plumage tone varies from dark in east to pale in west, with a broad area of intergradations in transition between eastern forest and western grasslands (Fig. 2); (2) wing length gradually becomes longer from south to north; (3) toe length decreases from east to west (Aldrich and Duvall 1958). However, recent analysis of these characteristics according to ecoregion groupings (Bailey and Cushwa 1981, Bailey 1983) showed these listings to be somewhat oversimplified, because measurements in some ecoregions run counter to general geographic trends (Aldrich 1993).

Subspecies

Five subspecies previously recognized by Aldrich and Duvall (1958) and Aldrich (1993). Subspecific characters and breeding ranges used in making the classifications are listed in Table 1. Ball and Avise (1992) examined mitochondrial DNA from geographically distinct populations of Z .m. marginella and Z. m. carolinensis in Washington, Minnesota, and Georgia. They found little differentiation between these populations and concluded that separation of these two groups into sub-species had minimal genetic support. Similarily, Johnson and Clayton (2000a) found little differentiation between populations in Texas and Arizona from analyses of mitochondrial and nuclear DNA. Molecular phylogenetic relationships within and among other previously suggested sub-species have not been examined.

Goodwin (1983) considered Z. graysoni (Lawrence 1871) and Z. macroura to be conspecifics. However, Z. graysoni, now extirpated from native haunts (Socorro I. off w. Mexico), was accorded full species status (Am. Ornithol. Union 1983) following morphological and behavioral research on caged birds (Baptista et al. 1983). Its status as separate species has received further support from recent molecular analyses (Johnson and Clayton 2000a,b).

Related Species

Most closely related to the Socoro Dove (Z. graysoni; Goodwin 1983, Johnson 2000a). Socoro Dove likely derived from mainland populations of the Mourning Dove (Goodwin 1983); molecular clock estimates place this colonization (450,000 YBP) around the time of the geological formation of Socoro Island (500,000 YBP; Johnson 2000a). Closely related to the Eared Dove (Z. auriculata) with which Goodwin (1983) considered the group to form a superspecies. Among other congeners, secondarily related to the Zenaida Dove (Z. aurita) and Galapagos Dove (Z. galapagoensis), with the White-winged Dove (Z. asiatica) and Pacific Dove (Z. meloda) being most distant (Goodwin 1983, Johnson 2000a).

Among extant species, sister taxa include Leptotila and secondarily Geotrygon (Johnson 2000b, 2001). Among other New World Columbiformes, the group formed by the preceding species is sister to New World Patagioenas, while ground doves (Columbina, Scardafella, Claravis, and Metriopelia) are distant in relationship (Johnson 2000b, 2001). Affinities to the Passenger Pigeon (Ectopistes migratorius) suggest Mourning Dove may be more closely related phylogenetically to that species than to Z. asiatica (Goodwin 1983). However, recent analysis supported a more distant relationship with Passenger Pigeon, occurring within a clade including Macropygia, Streptopilia, and Columba (Shapiro et al. 2002).