Yellow-browed Sparrow

The yellow-browed sparrow is a small American sparrow, measuring 13 cm (5 in) in length, with a mass between 14.5 and 19 g (0.5 and 0.7 oz). Sexes are similarly plumaged, though males average very slightly larger than females. The adult is brownish gray on the upperparts, with dusky streaks on the back. Its underparts are whitish, shading to grayish on the chest and buff on the flanks. Its legs are pinkish-brown, while the beak is horn-colored, with a darker culmen. Its iris is reddish brown. The juvenile, which has no yellow on its face or wings, is buffier than adults are, with thin brownish streaks on its breast and flanks.

Similar species. Although quite similar to the grassland sparrow, the yellow-browed sparrow typically shows more yellow on its face. It is overall paler and less streaked than the grassland sparrow, and lacks chestnut edges to its flight feathers. It is best told by its buzzy song, its less secretive behavior and less restrictive habitat preferences.

Although its former habitat was largely along rivers and on islands, the yellow-browed sparrow is now widespread in grassy areas of the Amazon biome, including agricultural fields, roadsides and around towns. It is generally found in the lowlands, though it has been recorded to 1,000 m (3,281 ft) on the east side of the Andes, and regularly as high as 1,500 m (4,921 ft) — and sometimes to 2,000 m (6,562 ft) — in Ecuador.

The yellow-browed sparrow is generally easier to see than its sister species is. It is less secretive, and is found in a wider range of grasslands.

Food and feeding. Like most American sparrows, the yellow-browed sparrow is largely granivorous, feeding on the seeds of native grasses and various introduced plants. It also eats insects, including larvae. It typically feeds on the ground.

Breeding. Breeding has been recorded between February and September. The yellow-browed sparrow builds a cup nest of dried grass lined with fine plant material. The nest is generally on the ground in a grass clump, though sometimes it is placed low in a shrub. The female lays 2–3 white eggs.

Voice. The yellow-browed sparrow's high-pitched song is described as "insect-like". Monotonous and buzzy, it is transcribed as tic, tzzz-tzzzzz, with the first note weak and short. The male sings throughout the day from a low, exposed perch.