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Cnemarchus erythropygius

Red-rumped Bush-Tyrant

  • Order: Passeriformes
  • Family: Tyrannidae
  • Polytypic 2 Subspecies

Authors: Schulenberg, Thomas S., and Guy M. Kirwan

Identification

Summary

Red-rumped Bush-Tyrant is a large, long tailed tyrant flycatcher. The back and wings are are dark brown, contrasting with an orange red rump, orange red bases to the outer rectrices, and white tertials. The head is light gray, becoming even paler on the forecrown and throat. The breast is brownish gray, but the belly is bright orange red.

Similar Species

The striking rufous, gray and white plumage pattern of Red-rumped Bush-Tyrant is distinctive. 

Vocalizations

Red-rumped Busy-Tyrant is not very vocal (Fjeldså and Krabbe 1990). A vocalization that is believed to be the song of Red-rumped Bush-Tyrant is described as "a rather unpatterned series of mellow mewed whistles and rich churring notes" (Lane, in Schulenberg et al. 2010). Other vocalizations include "faint scratching sounds kerk-kekkek" (Fjeldså and Krabbe 1990), "a short burry whistle" (Fjeldså and Krabbe 1990), and "loud, piercing, clear TEEER!, PEEP, pee-ip, and tew notes and burrier dzeeer and djip notes" (Lane, in Schulenberg et al. 2010).

Additional audio recordings of vocalizations of Red-rumped Bush-Tyrant can be heard at Macaulay Library and at xeno-canto.

Nonvocal Sounds

None reported.

Detailed Description (appearance)

The following description is based on Fjeldså and Krabbe (1990):

Adult: Sexes similar. Forecrown white, shading into a hoary gray crown. Back dark gray brown. Wings dark gray brown, except for extensive white on tertials. Rump rufous. Central rectrices blackish; remaining rectrices rufous, with blackish distal quarter. Chin and throat white, narrowly streaked dusky. Breast gray brown shading to rufous belly and undertail coverts.

Juvenile: Similar, but less white on forecrown.

Bare Parts

Iris: brown

Bill: black

Tarsi and toes: black

Bare parts color data from specimens in the Louisiana State University Museum of Natural Science.

Measurements

Total length: 20 cm (Fjeldså and Krabbe 1990), 23 cm (Hilty and Brown 1986, Ridgely and Tudor 2009)

Linear measurements (from Wetmore 1946):

male (n = 8)

wing length, mean 143.7 mm (range 141.7-146.1 mm)

tail length, mean 107.1 mm (range 103.7-112.0 mm)

culmen length (from base), mean 19.6 mm (range 18.7-20.2 mm)

tarsus length, range 28.2-31.6 mm

female (n = 7, except where otherwise indicated)

wing length, mean 143.1 mm (range 141.0-145.4 mm)

tail length, mean 107.6 mm (range 106.5-109.4 mm)

culmen length (from base), mean 20.2 mm (range 19.5-20.5 mm, n = 6)

tarsus length, mean 30.0 mm, range 29.2-30.6 mm

Mass: 50 g (n = 1, female; personal observation, specimen in the Louisiana State University Museum of Natural Science).

Molts

Undescribed.

Geographic Variation

Two subspecies often recognized (Traylor 1979), although these not well differentiated (Fjeldså and Krabbe 1990, Farnsworth and Langham 2004):

orinomus Wetmore 1946; type locality above Mamancanaca, Sierra Nevada de Santa Marta, Colombia, between 11,400 and 12,ooo ft [= 3475-3940 m]

Occurs in the Sierra Nevada de Santa Marta and the northern eastern Andes of Colombia

Similar to nominate erythropygius, but "brown of posterior lower surface and rump paler; brown area of dorsal surface confined to rump, and not extending so high on lower back; slightly grayer above; hindneck and back of head slightly darker; dark tips on lateral rectrices shorter; under wing-coverts paler" (Wetmore 1946).

erythropygius (Sclater); type locality Ecuador, restricted by Zimmer to Verdecocha, Pichincha, Ecuador

Occurs from southern Colombia south to Ecuador, Peru, and Bolivia. See Detailed Description.

Systematics

Red-rumped Bush-Tyrant has been classified as a member of Myiotheretes (e.g, Traylor 1979), but Lanyon (1986) returned erythropygius to the genus Cnemarchus Ridgway 1905.

Recommended Citation

Schulenberg, Thomas S., and Guy M. Kirwan. 2012. Red-rumped Bush-Tyrant (Cnemarchus erythropygius), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=467596