Fawn-breasted wren

The fawn-breasted wren (Cantorchilus guarayanus) is a species of bird in the family Troglodytidae. It is found in Bolivia, Brazil, and Paraguay.

Taxonomy and systematics
The fawn-breasted wren has sometimes been treated as conspecific with the buff-breasted wren (Cantorchilus leucotis), though they have very different vocalizations. The species is monotypic.

Description
The fawn-breasted wren is 13.5 cm long and weighs 13 to 14 g. Adults have a plain medium brown crown and upperparts that becomes rufescent on the lower back and rump. Their tail is reddish brown with crisp black bars. They have a narrow white supercilium mostly behind the eye, cheeks mottled gray-white and blackish, and black malar and moustacial stripes. Their chin is whitish, the chest a warm orange-buff, and the belly and vent area a deeper orange-buff. Juveniles are similar but their facial markings are less distinct.

Distribution and habitat
The fawn-breasted wren is found across much of northeastern Bolivia, a fairly thin slice of adjacent western Brazil, and a small part of northeastern Paraguay. It inhabits várzea scrubland and secondary forest, mostly near water. In elevation it ranges up to approximately 400 m.

Feeding
The fawn-breasted wren forages in pairs during the dry season and small family groups after nesting. It hunts in dense growth, usually from the ground up to 4 m above it, but sometimes as high as 10 m. Its diet has not been documented.

Breeding
Only a few fawn-breasted wren nests have been described, and little has been published about its breeding phenology. Nests are a flimsy dome of grasses and root hairs with a side entrance placed up to 3 m above ground in weeds, bushes, or the base of a small palm. The clutch size is two.

Vocalization
The members of a fawn-breasted wren pair sing antiphonally, the male's part a "cheerilo-choli" and the female's "pew-pew, pew-pew". Calls include a repeated "pew-pew" and harsh clicks.

Status
The IUCN has assessed the fawn-breasted wren as being of Least Concern. Though its population size has not been determined, it is believed to be fairly common to common across its range.