Order
Passeriformes
Family
Mimidae
Genus
Toxostoma
 
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Version 1.0

This is a historic version of this account.  Current version

SPECIES

Ocellated Thrasher Toxostoma ocellatum

Carlos A. Soberanes-González, Claudia I. Rodríguez-Flores, Marîa del Coro Arizmendi, Guy M. Kirwan, and Thomas S. Schulenberg
Version: 1.0 — Published April 4, 2014

Appearance

Distinguishing Characteristics

Toxostoma thrashers have long, graduated tails, a long decurved bill, and and relatively stout tarsi. Ocellated Thrasher has dark brown upperparts, a pale supercilium, and whitish underparts that are boldly marked with black spots, especially on the breast. The sexes are similar.

Similar Species

There are no similar species in the range of Ocellated Thrasher. Curve-billed Thrasher (Toxostoma curvirostre) lacks the pale supercilium, has paler irides, has a somewhat shorter bill, and its breast spotting is much more diffuse.

Detailed Description

The following description is based on Ridgway (1907); see also Geographic Variation:

Adult: Sexes similar. Upperparts dark brown, with a slight olive wash. The three or four outermost rectrices narrowly tipped with white. Middle and greater wing coverts tipped with a triangular white spot, forming two wingbars. Lores dull brownish white or pale brownish buff, more or less mottled with grayish or dusky. Supercilium dull brownish white, pale brownish buff, or grayish. Auriculars brown, with narrow pale shaft streaks. Lateral throat stripe blackish. Upperparts dull white or buffy white, becoming dull buff on belly, and with brown on the flanks; breast, sides, and flanks boldly spotted with black, the spots very large on the breast.

Juvenile: Face and underparts less distinctly marked; underparts with blurry blackish spots; and wingbars and tips of outer rectrices washed with buff (Howell and Webb 1995).

Molts

Molts of Ocellated Thrasher are undescribed. Presumably this species follows the complex basic molt strategy, as do other species of mimids (Pyle 1997, Howell 2010).

Bare Parts

Iris: dark brown

Bill: blackish, blackish gray

Tarsi and toes: blackish gray

Bare parts color data from Ridgway (1907) and Brewer (2001).

Measurements

Total length: 26.5-29.5 cm (Howell and Webb 1995), 27-29 cm (Ridgway 1907)

Linear measurements (from Ridgway 1907):

male (n = 4)

wing length: mean 102.7 mm (range 100-104 mm)

tail length: mean 140.7 mm (range 136-144 mm)

bill length (exposed culmen): mean 33 mm (range 32-33.5 mm)

tarsus length: 37.9 mm (range 37-38.5 mm)

female (n = 2)

wing length: mean 97.5 mm (range 96-99)

tail length: mean 132.5 mm (range 130-135 mm)

bill length (exposed culmen): mean 32 mm (range 31-33 mm)

tarsus length: mean 36 mm (range 35.5-36.5 mm)

Mass:

mean 84.3 g (range 77.7-88.9, n = 3, sex undetermined; Dunning 2008)

male: mean 89.9 g (range 84.0-95.8 g, n = 2; specimens in the Museum of Vertebrate Zoology, University of California, Berkeley)

female: mean 82.8 g (range 77.3-88.5 g, n = 9; specimens in the Museum of Vertebrate Zoology, University of California, Berkeley)

Recommended Citation

Soberanes-González, C. A., C. I. Rodríguez-Flores, M. d. C. Arizmendi, G. M. Kirwan, and T. S. Schulenberg (2014). Ocellated Thrasher (Toxostoma ocellatum), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.ocethr1.01