Peculiar modifications of certain primary feathers are worthy of mention and are very reminiscent of those noted by Zimmer (1939) for C. subbrunneus (Fig. 1). The twisted orientation of the leading edge of the wing is immediately obvious and very like that noted for C. subbruneus (Zimmer 1939). Primary 10 has a strongly curved leading edge. Primaries 9 through 5 have noticeable emarginations, least exaggerated on primary 9. There is a "bulge" of slightly decomposed barbs on primaries 8, 7, 6, and 5 more basal than the emarginations. These are similar to decomposed barbs on primaries 7, 6, and 5 of C. subbrunneus. In addition to the unique primary modifications, both species of Cnipodectes share a darkened, longitudinally raised "ridge" that is a narrowing of the vane of the inner webs of primaries 8, 7, and 6 (and 5 in C. superrufiis). The shaft structure of these primaries also has the same T-shaped cross-section noted by Zimmer (1939) for C. subbrunneus. Although the evidence is not conclusive, some or all of these feather modifications may be involved in the production of mechanical sound (see below).
Mechanical noises have been noted in both species of Cnipodectes. Hilty and Brown (1986: 483) note that C. subbrunneus "can produce a very audible pr'r'r'r'r'r' in flight with wings." This description is similar to mechanical sounds T.V.H. witnessed, performed by C. superrufus at Kirigueti. In response to playback, Valqui observed the bird approaching aggressively, making an accelerating and decelerating buzzing noise, while flying ca. 4 m off the ground. Although it was not clear what the source of the sound was (and it was not tape recorded), it seems likely that it was mechanical and produced by the wings.
Holotype.- MUSM 14023; adult male, netted at Puesto de Vigilancia Pakitza on the left (north) bank of Río Manu (approximately 11°56'S, 71°15'W) in the Zona Reservada del Parque Nacional Manu, elevation 350 m; 22 February 1990 by Grace P. Servat, field number 322. Measurements.- Wing chord 114 mm; tail length 112 mm; bill length (from posterior edge of nares to tip of maxilla) 11.4 mm; bill width (at nares) 6.6 mm; tarsus length (from tibiatarsus/tarsometatarsus joint to ventral base of 19 mm; mass 35 g; testis 4x2.5 mm.
Paratypes. - In addition to the holotype, there are four additional specimens of C. superrufus. Two were netted on the Río Pavoreni close to Kirigueti and prepared by T. Valqui H. A female (MUSM 26447), collected 23 February 2004: 26.3 g; no fat; molt on the two innermost primaries; ovary, 7 × 3 mm; ova minute.
Members of the ERM team netted the fourth specimen in June 2004 at Nuevo Mundo, but we have no further information about this individual. Finally, a fifth specimen was netted at Las Malvinas, Department of Cuzco, prepared by C. Aucca C, and deposited at MUSAAC.The specimen is a male (no institutional or personal catalogue numbers are available), collected 21 September 1997: 29.5 g; little fat; molt on body; left testis, 6.5 × 3.5 mm, right testis, 4 × 2.5 mm; skull 70% ossified; iris white or pale cream (it is not clear whether this was recorded in life or after death, when the color may have faded); maxilla gray with yellow base; mandible yellowish-pink; legs pale bluish-gray. Inspection of the specimen showed that it did not have the modified primaries we noted on the other two male specimens. Thus, we suspect that it represents a first basic male plumage.
Description of the holotype.- Feathering of crown and auricular areas are between Mahogany Red and Auburn (capitalized colors from Ridgway ) with the centers of the elongated "crest" feathers Raw Umber. Loral area with feather bases Ochraceous-Salmon, tips more rufescent; rictal bristles tipped blackish. Back feathers a rich Mahogany becoming intermediate between Mahogany and Burnt Sienna on the rump and uppertail coverts. The chin and upper throat have feather bases Zinc Orange with tips more like Sanford's Brown. There is a broad, ill defined pectoral band that is between Burnt Sienna and Sanford’s Brown. The belly and flanks are between Sanford's Brown and Xanthine Orange with the vent and undertail coverts a richer color between Burnt Sienna and Sandford's Brown. The uppertail coloration is Chestnut Brown on the inner webs and basal outer web of each rectrix. The edge of the outer web, which has a decomposed texture, is a richer color between Mahogany Red and Burnt Sienna. The undertail is a drabber Prout's Brown with the very inner edge of each rectrix Argus Brown. The secondary wing covert feathers (including greater, median, and lesser coverts) are Raw Umber with discrete edging of Mahogany Red. The leading edge of the primary coverts and underwing lining are Xanthine Orange. The primary coverts are Bone Brown. The Primaries have the basal shaft area Bone Brown with the outer portions Olive Brown becoming very pale on the basal inner primary webs. The secondaries are Olive Brown with the very outer edge Sudan Brown. The tertails have the interiors Prout's Brown with a broad inner edge Tawny and an outer edge between Brussels Brown and Auburn Brown. The undersides of the remiges fade to pale Vinaceous-Fawn by the basal inner edge.
Wing feather modification: Peculiar modifications of certain primary feathers are worthy of mention, and are very reminiscent of those noted by Zimmer (1939) for Cnipodectes subbrunneus. The twisted orientation of the leading edge of the wing is immediately obvious, and very like that noted for C. subbruneus (Zimmer 1939). Primary 10 has a strongly curved leading edge. Primaries 9 through 6 have noticeable emarginations, these becoming most exaggerated on primaries 8, 7, 6, and 5. There is a "bulge" of slightly decomposed barbs on primaries 6 and 5 more basal than the emarginations. This is similar to decomposed barbs on primaries 7. 6. and 5 of C. subbrunneus. The inner webs of these same three primaries exhibit the darkened longitudinally-raised "ridge" that is a narrowing of the vane (Zimmer 1939). The shaft structure of these same primaries also has the same "T" shaped cross-section as noted by Zimmer (1939) for C. subbrunneus. Although the evidence is not conclusive, some or all of these feather modifications may be involved in the production of mechanical sound (B. Whitney, pers. comm.; pers. obs.).
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
Habitat and Ecology
IUCN Red List Assessment
Red List Category
Red List Criteria
Two Peruvian sites, Pakitza and Playa Bonita are within the Manu Biosphere Zone (Lane et al. 2007). Several surveys have targeted and identified this species, improving knowledge of its global distribution. Conservation Actions Proposed
Confirm the species's distribution by checking additional Guadua sites that may support it. Study its ecology assessing whether there is a relationship between presence and bamboo patch size/patch maturity. Map the potential impact of development projects within its range to assess future population declines and identify key sites for conservation/mitigation.
It is associated with bamboo growing in humid forested regions in south-eastern Peru, northern Bolivia and far western Brazil (Acre only). Most of its range is remote. Nevertheless, it has recently been estimated that the total population is below 10,000 individuals, leading to recommendations of treating it as vulnerable, and this was followed by BirdLife International in 2009. As suggested by its common name, its primaries are modified as in the related, but smaller, brownish twistwing. Unlike the brownish twistwing, the rufous twistwing is bright rufous overall.
In 2009, Andrew Spencer recorded the effect of the twist in the wings of the rufous twistwing. To hear the sound, follow the link at the bottom of this page.
- Lane, D., G. P. Servat, T. Valqui H., & F. R. Lambert. 2007. A distinctive new species of Tyrant flycatcher (Passerifomer: Tyrannidae: Cnipodectes) from south-eastern Peru. Auk. 124(3): 762–772.
- Tobias, J. A., D. J. Lebbin, A. Aleixo, M. J. Andersen, E. Guilherme, P. A. Hosner, & N. Seddon. (2008) Distribution, Behaviour and Conservation Status of the Rufous Twistwing Cnipodectes superrufus. The Wilson Journal of Ornithology 120(1): 38–49.
- BirdLife Species factsheet
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