Pectoral Sparrow

The pectoral sparrow is sexually dimorphic, and, as the name implies, sparrow-sized, at 15 cm (5.9 in) in length and 24 g (0.85 oz) in weight. Its upperparts are pale green, becoming yellow near the bend of the wing. The head is black, with white on its throat and as stripes on its crown. Its underparts are white in males and creamy in females, with males also having a broad black band going across its breast (a pectoral band). The beak is also black, roughly 14–15 mm (0.55–0.59 in) long for both males and females. Tails are 58–60 and 64–67 mm (2.3–2.4 and 2.5–2.6 in) and wings are 74–75 and 76–80 mm (2.9–3.0 and 3.0–3.1 in) for males and females respectively. Its iris is brown, and its tarsi and toes are pinkish gray. Male and female plumage are different, with females having dull olive upperparts instead of bright yellow, are a grayish pectoral band. The pectoral sparrow is fairly unique in its habitat, usually being the only small forest sparrow with a striped head in its range. It can be differentiated from the orange-billed sparrow, which it borders distribution with in eastern Columbia, by the namesake orange bill, as well its inverted throat colors (black throat with a white stripe).

The pectoral sparrow is non-migratory and can be found everywhere in the Amazon Basin east of the Andes except for the western parts between the Negro and Purus rivers. Besides the Amazon jungle, it is found in eastern and north-eastern Brazil. It occupies altitudes up to 1,500 m (4,900 ft) in southern Venezuela, 1,000 m (3,300 ft) in southeastern Peru, and 1,300 m (4,300 ft) in Bolivia. It occupies the lowland undergrowths of humid evergreen forests or secondary forests, and infrequently in lighter woodlands or coffee plantations, often when near humid wooded ravines. Pair density in Peru was reported to be about 1 pair per 200 hectares (490 acres).

Feeding behavior is not well studied. The pectoral sparrow has been observed foraging on the ground, mainly eating insects and seeds, and to a lesser extent various fruits. Studies on stomach contents in Brazil and Suriname showed various beetles, true bugs and ants, along with other insects and a small amount of grass and seeds. Adults have been observed bringing insect limbs to the nest for feeding.