Streaked Xenops

Identification

The streaked xenops is about 12 to 13 cm (4.7 to 5.1 in) long and weighs 10 to 15 g (0.35 to 0.53 oz). Its bill is wedge-shaped, short, and thick. The sexes are alike. The nominate subspecies X. r. rutilans has somewhat variable plumage. Adults generally have a conspicuous buff supercilium and a pure white malar stripe on an otherwise brownish face with some darker and lighter highlights. Their crown is dark brown with rufous streaks. Their back is rufescent brown with faint paler rufous streaks, their rump and uppertail coverts plain chestnut-rufous, and their tail chestnut-rufous with a blackish inner web on one pair of feathers. Their wing coverts are rufescent-brown with darker inner webs and their flight feathers are dark fuscous and all but the inner pair have a rufous tinge on their outer webs. Their throat and uppermost breast are whitish with darker mottling. The rest of their underparts have wide buffy whitish streaks with dark brownish edges on a medium brownish background; the streaks narrow and fade on the lower belly. Their iris is brown to dark brown, their maxilla dark brown to blackish, their mandible whitish to pinkish gray with a blackish tip, and their legs and feet gray to black. Juveniles differ from adults with less distinct streaking, less black on the tail, and a cloudy grayish throat.<p>The other 10 subspecies of the streaked xenops differ in varying degrees from the nominate, though much of the differences fall within the variability of the nominate's plumage. The differences tend to be in the intensity of the rufous of the upperparts, the size and exact color of the underparts' streaks, and the exact base color of the underparts.

Taxonomy

Early on the streaked xenops was assigned the binomial Xenops rutilus. In the mid 1900s taxonomists began using X. rutilans. By the principle of priority the earlier rutilus is correct but because of the long usage of rutilans most systems have stayed with that specific epithet. A major exception is BirdLife International's Handbook of the Birds of the World (HBW), which uses X. rutilus.<p>The major worldwide taxonomic systems recognize these 11 subspecies:

Scientific name

Xenops rutilans

Authority

Temminck, 1821

Order

Passeriformes

Family

Furnariidae

Genus

Xenops

Range and habitat

The 11 subspecies of the streaked xenops are found thus:<p>In the Andes and Central American mountains the streaked xenops inhabits montane evergreen and deciduous forests, mostly at elevations between 700 and 2,400 m (2,300 and 7,900 ft). In Costa Rica it occurs from 1,200 to 2,500 m (3,900 to 8,200 ft) and in Colombia from 1,400 to 2,800 m (4,600 to 9,200 ft). In the lowlands it inhabits a wide variety of forest and woodland landscapes that range from semi-arid to humid. They include tropical deciduous and tropical lowland evergreen primary forest and also secondary forest. It is found in the forest interior and at its edges. In Ecuador it reaches 2,000 m (6,600 ft) in the west and spans from 800 to 2,000 m (2,600 to 6,600 ft) in the east. Much of its Brazilian range is at low elevation but it reaches as high as 2,400 m (7,900 ft) in that country.

Migration

Resident species

Behavior

The streaked xenops is a year-round resident throughout its range.<p>The diet of the streaked xenops is arthropods. The larvae of wood-boring beetles have been documented as an item in addition to adult arthropods. Single birds and pairs often join mixed-species foraging flocks. They feed in the forest understory at its edges and from the mid levels to its subcanopy in the interior. It climbs and hitches along slender branches and sometimes uses its tail as a brace, catching prey by gleaning, chiseling, and flaking bark and rotten wood. It has also been observed catching flying termites in mid-air.<p>The streaked xenops' breeding season has not been determined in most of its range. In Costa Rica it spans from January to May and on Trinidad from February to May. It nests in a cavity, whether natural, excavated by a small woodpecker, or excavated itself, and adds a small amount of soft plant fiber to the bottom. Nests have been noted between 1.5 to 9 m (5 to 30 ft) above the ground. The clutch size is two or three eggs. The incubation period, time to fledging, and details of parental care are not known.<p>The song of the streaked xenops is "an ascending and then descending, high-pitched series of 5–10 dry, squeaky 'swee' or 'zeet' notes, accelerating at [the] end". Its calls are "a high, piercing 'peet' or 'cheet' ".

Conservation

Population trend

stable