Order
Passeriformes
Family
Corvidae
Genus
Corvus
 
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Version 1.0

This is a historic version of this account.  Current version

SPECIES

Tamaulipas Crow Corvus imparatus

Claudia I. Rodríguez-Flores, Carlos A. Soberanes-González, Marîa del Coro Arizmendi, Guy M. Kirwan, and Thomas S. Schulenberg
Version: 1.0 — Published November 8, 2013

Appearance

Distinguishing Characteristics

Crows (Corvus) are large, black passerines with stout tarsi and strong bills; they also have bristle-like feathers that cover the nares. Tamaulipas Crow is a small Corvus. The plumage is entirely glossy black; the head and upperparts have a purplish sheen, whereas the underparts are glossed with bluish to blue green. The sexes are similar, but juvenile Tamaulipas Crows are duller and sootier.

Similar Species

Tamaulipas Crow is very similar to Sinaloa Crow (Corvus sinaloae) of northwestern Mexico, but these two species are completely allopatric. Sinaloa and Tamaulipas crows also have different vocalizations, and the tail of Sinaloa Crow averages slightly longer (especially in males). Chihuahuan Raven (Corvus cryptoleucus) is much larger than Tamaulipas Crow, with a much heavier bill, a longer wedge shaped tail, and different vocalizations. The greater identification challenge is separating Tamaulipas Crow from males of Great-tailed Grackle (Quiscalus mexicanus), which are similar in overall length to the crow but are more slender with a longer, graduated, "keeled" tail, and pale irides.

Detailed Description

The following description of the adult is based on Ridgway (1904); Ridgway's description encompasses both Tamaulipas Crow and Sinaloa Crow (Corvus sinaloae), but no plumages differences are known between these two species:

Adult: Black, glossed purplish on the upperparts and bluish on the underparts. Crown, nape, wing coverts and secondaries glossy dark violet. Sides of neck, the back, scapulars, rump, uppertail coverts, and primary coverts glossy dark violet blue. Primaries and rectrices dark steel blue, the central rectrices tinged with violet, and the outermost primaries more greenish blue. Sides of head and the underparts dark steel blue or greenish steel blue, becoming more greenish posteriorly.

Juvenile: Duller than adult. Described by Goodwin (1976) as "duller and less lustrous but with more iridescence than is usual in juvenile crows"; Marzluff (2009), however, describes the juvenile as "dull black, with limited sheen".

Molts

Undescribed, but presumably are similar to those of other North American crows and ravens. If so, then Tamaulipas Crow follows the Complex Basic molt strategy. There is a preformative molt, which is partial; the outer coverts and the rectrices are retained. Subsequent prebasic molts are complete, and there is no prealternate molt (see Pyle 1997).

Bare Parts

Iris: brown, dark brown

Bill: black

Tarsi and toes: black

Bare parts color data from Ridgway (1904) and from Madge and Burn (1994).

Measurements

Total length: 35.5-39.5 mm (Howell and Webb 1995)

Linear measurements (from Johnston 1961):

male

wing length (chord): mean 250.5 mm SD 7.46 mm, range 231.0-265.5 mm, n = 27

tail length: mean 145.9 mm SD 7.45 mm, range 132.0-155.0 mm, n = 26

bill length (from anterior edge of nostril): mean 29.11 mm SD 1.74 mm, range 25.2-32.4 mm, n = 25

tarsus length: mean 39.59 mm SD 1.74 mm, range 36.2-43.0 mm, n = 25

female

wing length (chord): mean 238.4 mm SD 4.17 mm, range 232.5-246.0 mm, n = 10

tail length: mean 140.4 mm SD 3.04 mm, range 136.0-147.5 mm, n = 10

bill length (from anterior edge of nostril): mean 27.30 mm SD 1.14 mm, range 26.1-29.4 mm, n = 10

tarsus length: mean 38.33 mm, range 36.2-39.6 mm, n = 9

Mass: mean 221 g (range 192-237 g, n = 5, sexes combined; Dunning 2008)

Recommended Citation

Rodríguez-Flores, C. I., C. A. Soberanes-González, M. d. C. Arizmendi, G. M. Kirwan, and T. S. Schulenberg (2013). Tamaulipas Crow (Corvus imparatus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.tamcro.01