The Rufous Twistwing (Cnipodectes superrufus), a newly described Amazonian tyrant-flycatcher,
is known from five specimens and five localities in Cuzco and western Madre de Dios departments,
Peru. We report three additional specimens and eight new localities extending the known range of the species
east across Dpto. Madre de Dios, Peru, into Dpto. Pando, Bolivia, and Acre State, Brazil. The new localities
increase the distribution from 3,400 to 89,000 km2. We collected biometric data from five individuals, made
behavioral observations in the field, and recorded three separate types of vocalizations, two of which (including
the song) were previously unknown. We provide quantitative description of these vocalizations, consider their
function, and compare them with vocalizations of the only known congener, the Brownish Twistwing (Cnipodectes
subbrunneus). Unique vocal repertoires support the classification of these two forms as sister species.
The Rufous Twistwing resembles the Brownish Twistwing in producing loud vocalizations from regular song
posts and both species appear to have a polygamous mating system. We provide further evidence consistent
with the hypothesis the Rufous Twistwing is a Guadua bamboo specialist and recommend that it be listed as
Vulnerable on the IUCN Red List. Received 5 July 2006. Accepted 23 March 2007
|
