Order
Passeriformes
Family
Passerellidae
Genus
Xenospiza
 
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Version 1.0

This is a historic version of this account.  Current version

SPECIES

Sierra Madre Sparrow Xenospiza baileyi

Michael Gallegos
Version: 1.0 — Published June 20, 2014

Appearance

Distinguishing Characteristics

Sierra Madre Sparrow is a small bird, approximately 12 cm in length, in the family Emberizidae. Its upperparts are rufous, streaked with black, becoming grayer on the nape. There are blackish brown lateral crown stripes, and a gray supercilium and ear coverts. Sierra Madre Sparrow also has a blackish streak through the eye, and blackish moustachial and lateral throat stripes. The underparts are whitish, heavily streaked with black. The tail is relatively short and stout when this bird is perched. The sexes of Sierra Madre Sparrow are similar.

Similar Species

When first discovered in 1889, Sierra Madre Sparrow was misidentified as either a Song Sparrow (Melospiza melodia) or a Savannah Sparrow (Passerculus sandwichensis). It superficially resembles both of these species in general plumage with white underparts and dark streaking on throat, breast, and flanks. Song Sparrow is larger than the Sierra Madre Sparrow, however, with a longer, round-tipped tail, less rufous upperparts, and its underparts are duller with darker flanks; Song Sparrow also lacks the bright yellow at the bend of the wing of Sierra Madre Sparrow.

Detailed Description

Adult: The upperparts of Sierra Madre Sparrow are rufous with black streaks; feathers with grayish to buff edging producing a scalloped appearance in fresh plumage, and the outer scapulars are rufous. Wings and tail are dark brown, with rufous edging on the tertials, secondaries, and wing coverts, and with sandy gray brown or rufous edging on notched rectrices and primaries. Bend of wing is bright yellow. Lateral crown stripes of blackish brown with median gray streaking; gray supercilium; grayish auriculars with blackish postocular stripe and moustache; buffy subauricular region and black lateral throat stripe. Throat and underparts whitish with black streaks on chest and flanks, often merging into black central chest spot; chest, flanks, and undertail coverts have buff wash in fresh plumage (Dickerman et al. 1967, Howell and Webb 1995, Oliveras de Ita et al. 2001).

Juvenile: Dorsal plumage is dull overall, and has broad, central, black, shaft streaks edged with olive brown to olive buff, richer on the scapulars and interscapulars and grayer on the nape giving a "scalloped" effect; edges of tertials and remiges are ochraceous brown. Crown stripe is not well differentiated. Underparts are washed with dirty buff, and are weakly and variably streaked in brown rather than black in a band across the breast, as well as along the side of throat and breast but not on the flanks; streaks concentrate into a submalar streak in some individuals (Dickerman et al. 1967, Howell and Webb 1995; Oliveras de Ita et al. 2001). Further differs from adults in color of Bare Parts.

Molts

The first prebasic (post-juvenile) molt is incomplete, including only wing coverts and body. This molt occurs in the middle of July through September, though sometimes takes longer. There is some evidence of a partial prealternate molt involving the chin and malar area in some individuals (Dickerman et al. 1967).

Bare Parts

Iris: Grayish brown; the irides of juveniles are grayish brown to dark brown.

Bill: "Dusky bluish gray below, buffy at and before gonydeal angle". In juveniles, maxilla is drab to dark drab, mandible is drab with paler base and with paler tomia, buffy to ochre-tinged, especially basally; gonys also ochre-tinged. Howell and Webb (1995) describe juvenile bill as dull yellow-orange with dark culmen. Mouth is pale flesh to reddish, and maxillary palate is yellow.

Tarsi and toes: Buffy flesh to pale buffy drab, paler inside, with darker toes, especially joints, varying to drab.  Tarsi and toes of juveniles are flesh colored to darker, more drab, especially toes in older young.

Bare part color data from Dickerman et al. (1967).

Measurements

Morphometric data from Dickerman et al. (1967):

Recommended Citation

Gallegos, M. (2014). Sierra Madre Sparrow (Xenospiza baileyi), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.simspa1.01