The fulvous wren is long; males weigh an average of and females weigh . The nominate adults have a reddish brown crown and back that is redder on the rump. They have a buff
supercilium, a dull brown eye stripe, and buffy cinnamon cheeks. The tail is also reddish brown, and has narrow blackish bars crossing it. The throat is buffy white, the chest buffy cinnamon darkening to reddish brown on the flanks and belly.
C. f. fitzpatricki has a darker crown and a lighter supercilium than the nominate.
C. f. gravesi has a whitish supercilium and its underparts are paler than those of the nominate. The immature is similar to the nominate adult but its crown is grayish. ==Distribution and habitat==