Slaty Spinetail Synallaxis brachyura Scientific name definitions

The Slaty Spinetail is common in a variety of open woodland and shrubby habitats in the tropical and subtropical zones (200-3300m), ranging from the northern coast of Honduras to southwest Ecuador. It is often found foraging in family groups or pairs in low, dense vegetation. It has a uniformly dark gray body with deep rufous wing coverts and a rufous crown, extending from behind the forehead to the nape. The four subspecies recognized are separated both geographically and altitudinally. Brachyura is found in northern Colombia (mostly below 300m) and has a deep chestnut crown and a paler gray supercilium. Caucae is found mostly above 1,000m central Colombia is paler overall. Griseonucha of southwest Ecuador is darker overall with a silvery throat and some white in the belly. Nigrofumosa is found primarily above 1,000m in western Ecuador and western Colombia, and is similar to griseonucha but with a dark throat.

14–16 cm; 16–21 g. One of the darkest species in genus. Nominate race has deep rufous-chestnut crown and nape, greyish supercilium, darker grey rest of head, dark sooty-brown to slate-brown back, blending to slightly browner rump and uppertail-coverts; wing-coverts and bases of remiges deep rufous-chestnut, distal portions of remiges dark brown; tail long, graduated, 10 rectrices with stiffened shafts, disintegrated and pointed toward tips, distal 1–2 mm virtually bare of barbs and giving “spiny” appearance, colour as rump; throat blackish with paler margins on some feathers, breast and sides dark sooty-brown, belly paler and greyer, flanks and undertail-coverts browner; iris reddish-brown to orange-brown; upper mandible black to grey, lower mandible grey to blue-grey; tarsus and toes olive-grey, grey or blue-grey. Sexes alike. Juvenile lacks contrasting crown colour, has upperparts paler than adult, wing-coverts duller, throat patch less distinct and paler, underparts more olivaceous. Race <em>nigrifumosa</em> is darker throughout, crown and wings darker rufous, back darker brown, underparts  darker grey; griseonucha  is slightly paler than previous, especially on underparts  ; caucae  has paler crown, greyer back, paler greyish-olive rump and uppertail-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.

Dietary items recorded are Coleoptera, Hemiptera, larval Diptera and Lepidoptera, spiders, spider eggs, and seeds. Usually in pairs, foraging from undergrowth down to ground. Gleans arthropods from dead leaves, small branches, foliage, and leaf litter.

Song  a low “ch-ch-ch-churrr-r-r-r”, “je-ch-ch-chrrrrr” or “chut-chut-chrrrrrrrrrrr”, slightly descending at end, lasting c. 0·3 seconds, repeated at intervals of 1–2 seconds. Call during foraging “chk”; “chee-ah” also described.

Eggs in Jan–Feb and Apr–Oct in Costa Rica. Monogamous; paired throughout year. Nest a bulky mass c. 20–40 cm high and 40–50 cm long, of twigs and small sticks, often thorny, some as long as 25 cm, reptile skins also regularly incorporated, horizontal entrance tube 30–40 cm long (sometimes two separate tubes), possibly sometimes curved, inner chamber covered by denser thatch, floor lined with pad of soft green or pubescent leaves or fragments (usually of Solanum) mixed or bound with spider webbing and occasionally snake and lizard skins; placed in dense bush or small vine-covered tree, usually 0·5–5 m above ground. Clutch 2–3 eggs; incubation by both sexes, period 18–19 days; both also feed chicks, nestling period 17 days; fledglings independent in 30 days.