McCown's longspur (Calcarius mccownii) COSEWIC assessment and status report: chapter 3

Species Information

Name and classification

Order:

Passeriformes

Family:

Emberizidae

Genus:

Calcarius

Species:

mccownii

English common name:

McCown's Longspur

French common name:

Bruant de McCown

McCown's Longspur is classified as one of four species in the genus Calcarius (American Ornithologists' Union (AOU) 1998, Banks et al. 2003). Historically, the species was classified in the monotypic genus Rhynchophanes based on its morphological distinctions from the other Calcarius species (Rising 1996), but it was later placed in Calcarius after a Chestnut-collared Longspur (C. ornatus) X McCown's Longspur hybrid was described (Sibley and Pettingill 1955, With 1994a). Recent molecular evidence, however, suggests that Calcarius mccownii exists outside the Calcarius clade (Carson and Spicer 2003, Klicka et al. 2003) and so the species may be reclassified in the near future (Banks et al. 2003). No subspecies or geographic variants are recognized (With 1994a).

Description

McCown's Longspur is a chunky, sparrow-sized bird (length: 14-16 cm) with a thick bill and distinctive inverted black "T" pattern on a white tail (With 1994a, Rising 1996). Like other members of Calcarius it has an elongated hallux claw; hence, the common name "longspur" (With 1994a). Adult mass varies between 24 and 29 g. McCown's differs from the other Calcarius species in having a larger and thicker bill, shorter tail, and shorter hallux (Rising 1996).

Breeding males are gray with brownish-gray wings and a chestnut patch on the median wing coverts. They also have a black crown, malar stripe, and breast patch (Rising 1996). In winter, the black areas on the head are concealed by buff tips and the black breast patch is fainter and partially concealed by buff tips (Rising 1996). Females are grayish brown with brown streaking on the crown, back, and rump, lighter underparts, and faint chestnut in median wing coverts (With 1994a). Breeding and winter plumages differ only in the extent of streaking on the back (Rising 1996).

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