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Ramphotrigon fuscicauda

Dusky-tailed Flatbill

  • Order: Passeriformes
  • Family: Tyrannidae
  • Monotypic

Authors: Schulenberg, Thomas S., and Tom Johnson

Identification

Summary

Ramphotrigon flatbills are medium-sized, broad-billed tyrant flycatchers with dull olive green plumage and wing bars. The Dusky-tailed Flatbill is olive green above and yellow below, with a narrow yellow supercilium, blurry olive streaks on the throat and
breast, and dusky tail and wings; the wings also have rufous wing bars. 

Similar Species

Dusky-tailed Flatbill is most similar to Large-headed Flatbill (Ramphotrigon megacephalum), but Dusky-tailed Flatbill is larger, has a narrower superciliums, has blurry olive streaks on throat and breast, and has a dusky, not olive, tail. Olivaceous Flatbill (Rhynchocyclus olivaceus) has unstreaked underparts, and more olive wings and tail, lacking wing bars.

Vocalizations

The most frequent call of Dusky-tailed Flatbill is "a mellow whistle followed by a decelerating, descending musical chatter: PEEEWWW trrr'PEER-peer-pur" (Lane, in Schulenberg et al. 2010). Also has "a mellow falling-rising whistle: PEEeer'wee?" (Lane, in Schulenberg et al. 2010). The dawn song of Dusky-tailed Flatbill is "a descending mellow whistle followed by a musical hiccup PEEWW'wichwee", in which the terminal phrase may vary, e.g. PEEWW'weeher (Lane, in Schulenberg et al. 2010).

Additional audio recordings of Dusky-tailed Flatbill can be heard at Macaulay Library and at xeno-canto.

Nonvocal Sounds

None reported.

Detailed Description (appearance)

The following description is based on Chapman (1925):

Adult: Sexes similar. Upperparts dark olive, the crown slightly darker; uppertail coverts slightly lighter than the back. Narrow yellow green line above the eye; area immediately below the eye also narrowly yellow green. Rectrices brownish fuscous-black, feathers narrowly margined with buffy citrine. Remiges fuscous-black, the primaries very narrowly margined with buffy olive, the secondaries and tertials with old gold; coverts widely margined with rufous brown or cinnamon. Lores grayish. Throat and upper breast olive green streaked with yellow; lower breast and sides yellow streaked with olive green; center of the belly and undertail coverts citron yellow; bend of wing tinged with ochraceous; lower wingcoverts citron yellow.

Bare Parts

Iris: dark brown

Bill: maxilla black; mandible black, with a pinkish base

Tarsi and toes: gray, dark gray

Bare parts color data from specimens in Field Museum of Natural History.

Measurements

Total length: 15.5 cm (Ridgely and Greenfield 2001b), 16 cm (Schulenberg et al. 2010), 16.5 cm (Hilty and Brown 1986)

Linear measurements:

wing length, 68 mm; tail length, 63 mm; culmen length, 16 mm (n = 1, female; Chapman 1925)

Mass: mean 18.6 g (range 16.5-20.5 g, n = 12, sexes combined; Parker 1984)

Molts

No information available - Contribute

Geographic Variation

Monotypic.

Systematics

The genus Ramphotrigon formerly was considered to be related to Tolmomyias and Rhynchocyclus, two other genera of small tyrant flycatchers with broad bills (e.g. Hellmayr 1927, Traylor 1979). Lanyon (1985), however, proposed that Ramphotrigon was more closely related to Myiarchus, due to shared derived features of the cranium and syrinx, and to shared similarities in nest site. Two recent phylogenetic analyses of DNA sequence data (Ohlson et al. 2008, Tello et al. 2009) yielded somewhat incongruent information on the relationships of Ramphotrigon. Both studies confirmed, however, that Ramphotrigon is not at all closely related to Tolmomyias or Rhynchocyclus. Tello et al. (2009) found that Ramphotrigon is basal to a clade that includes Myiarchus (as well as Tyrannus and related genera), but Ohlson et al. (2008) reported that Ramphotrigon clustered with fluvicoline flycatchers.

Recommended Citation

Schulenberg, Thomas S., and Tom Johnson. 2012. Dusky-tailed Flatbill (Ramphotrigon fuscicauda), 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=471916