Yellow-chinned Spinetail Certhiaxis cinnamomeus Scientific name definitions

The Yellow-chinned Spinetail is a furnariid that is distributed across tropical and subtropical South America, though is scarce or absent in western Amazonia and along the Pacific coast. This species is strongly associated with water and occurs in a variety of marsh habitats, such as reed beds, ditches, wet grassy areas, mangroves and bordering shrubbery. Despite the eponymous common name and its conspicuous behavior, the yellow chin is difficult to see; this species best is identified by its simple bicolored appearance (rufous above, white below), habitat and its frequently uttered churring rattle. Its sister species, the Red-and-White Spinetail (Certhiaxis mustelinus), of Amazonian river islands, is very similar and both often occur in the same vicinity. Where the two species overlap, Yellow-chinned is separated by its duller rufous back, pale grayish superciliary and lack of sharply contrasting black lores.

13–16 cm; 13–17 g. A crisply patterned spinetail mainly reddish above and whitish below. Nominate race has grey super­cilium, broad dusky brown eyeline, greyish rest of face; crown reddish-brown, becoming slightly paler on back; rump paler rufescent brown, long uppertail-coverts darker and redder; wings bright rufous, dark fuscous tips of remiges; tail graduated, 12 rectrices with stiffened shafts, distal 5–10 mm nearly lacking in barbs, producing very “spiny” appearance, mostly rufous, central pair with duller brown inner webs; chin and centre of upper throat pale yellow, rest of throat white; breast and belly creamy white, sides pale grey-brown, flanks and undertail-coverts tawny brownish; iris reddish-brown to pale orange to whitish (source of variation unknown, possibly geographical); upper mandible blackish, lower mandible uniform black to grey with black tip; tarsus and toes bluish to greyish to silvery slate. Differs from similar C. mustelinus mainly in having pale supercilium, yellow on throat, 12 rather than 10 rectrices. Sexes alike. Juvenile lacks yellow on chin, has darker and less rufescent upperparts, underparts occasionally faintly mottled. Race fuscifrons has dusky brown forehead; marabinus has the most reddish upperparts of any race, differs from nominate also in having dusky greyish forehead, whiter supercilium; valencianus differs from previous in less reddish upperparts, darker, more dusky underparts, greyish supercilium; <em>orenocensis</em> is palest, dullest, least rufescent race, with back sandy brown, contrasting with wings and crown, also dusky spot on distal portion of inner webs of central rectrices; pallidus is evidently like last but brighter rufescent above, and much paler throughout than nominate; cearensis is like previous but brighter generally, has darker sides and flanks; <em>russeolus</em> is like last, but has browner, less rufescent upperparts, more greyish flanks and undertail-coverts.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Freshwater marshes and edge of mangrove forest; found in a variety of wetlands with mix of grass, shrubs, and emergent and floating vegetation, including on old river islands in Amazonia; also overgrown ditches. Sea-level to 500 m, locally to 750 m. Locally syntopic with C. mustelinus, but habitat differences between them not clear.

Resident.

Recorded dietary items are Coleoptera, Lepidoptera larvae, Hemiptera, Odonata, Hymenoptera including ants, Orthoptera, Diptera, Isoptera, spiders and 1 crab (Uca thayeri). Forages singly or in pairs, usually on or within 2 m of ground, occasionally to c. 3 m. Gleans arthropods from small branches and foliage, occasionally from water or ground.

Sings frequently; churring rattle, “chu-chuchchchchchchchchchchcu”, often as duet, also described as low-pitched trill 1–2 seconds long that ascends and then fades (reminiscent of song of a Laterallus rail); also gives short thin trill. Call a sharp “krip” or “chip”.

Breeds throughout year in coastal Surinam, and primarily during Aug–Oct dry season in French Guiana; active nests in Apr–Oct in W Venezuela; breeding recorded Jun–Oct (Jun peak in egg dates) in Trinidad; eggs in Oct in S Brazil; eggs in Oct–Dec and nestlings in Nov–Dec in Argentina. Presumably monogamous. Nest a bulky, globular mass c. 25–40 cm long, c. 20–30 cm high, made of interwoven sticks, often thorny ones, interior curving tube c. 20–25 cm long leading vertically from top or end to nest-chamber, latter c. 10 cm in diameter, sometimes lined with soft plant material; placed low in bush or grass, usually near or over water, 0·2–1·5 m up, rarely as high as 9 m, often between roots when in mangrove forest; new nest sometimes superimposed on old one. Wires used as nest material in urban areas of Brazil (1 Pereira, G.A. (2011). Ninhos de Certhiaxis cinnamomeus (Passeriformes: Furnariidae) construídos com material metálico em Pernambuco, Brasil. Atualidades Ornitológicas. 159: 4–6. Close ). Clutch 2–5 eggs. Nests regularly parasitized by Striped Cuckoo (Tapera naevia).

Not globally threatened. Common to abundant in much of its large range. Restriction to wetlands makes it susceptible to the usual suite of conservation problems that afflict wetland species, e.g. drainage and pollution. Occurs in numerous protected areas.