Olive sparrow

The olive sparrow (Arremonops rufivirgatus) is a species of bird in the family Passerellidae, the New World sparrows. It is found from Texas to Costa Rica.

The olive sparrow is about 12 to 14 cm (4.7 to 5.5 in) long and weighs 15 to 30 g (0.53 to 1.1 oz). The sexes have the same plumage. Adults of the nominate subspecies have a brown crown with a wide olive gray stripe through its middle and down the nape. They have drab to olive brown lores, a wide buffy gray supercilium, and a thin brown line through the eye on an otherwise gray face. Their upperparts are uniformly olive. Their tail is brownish olive to olive with light yellowish outer edges on the feathers. Their wings' lesser coverts are mostly yellow with a few that are light fuscous with yellowish olive edges. Their primaries and secondaries are fuscous with buff inner edges and light yellowish olive outer edges. Their chin and throat are buffy white, their breast and belly white to buffy white, their sides and flanks buff, and undertail coverts cinnamon or creamy buff.

The other subspecies of the olive sparrow differ from the nominate and each other thus:

A. r. crassirostris: darker and browner than nominate with dark olive-green upperparts and dark buffy olive flanks

A. r. rhyptothorax: black-striped chestnut crown with gray center, light brownish olive back, whitish breast and belly, and ashy brown flanks

A. r. verticalis: chestnut crown with gray center, brownish olive back, and olive-gray flanks

A. r. sinaloae: chestnut crown with pale gray center, buff-gray ear coverts, grayish olive upperparts, and buffy gray flanks

A. r. sumichrasti: similar to sinaloae with darker crown, buffier ear coverts, and greener (less gray) upperparts

A. r. chiapensis: chestnut crown with dark gray center, darker green upperparts than sumichrasti

A. r. superciliosus: dark chestnut crown with buffy gray center, grayish buff ear coverts, medium olive-green upperparts, and buffy gray flanks

All subspecies have a reddish brown to brownish red iris, a brownish pink bill with a darker base and tip, and pinkish to brownish pink legs and feet.