Mouse-colored Antshrike Thamnophilus murinus Scientific name definitions

Despite some degree of geographical overlap in upper Amazonia, west of the Rios Madeira and Negro, the Mouse-colored Antshrike is, more or less, the northern replacement of the vocally very similar Plain-winged Antshrike (Thamnophilus schistaceus). The present species, which is generally fairly common, occurs across the Guiana Shield, thence west to eastern Ecuador and Peru, and south to northernmost Bolivia, and is almost wholly restricted to lowland terra firme forest, whereas the Plain-winged Antshrike appears to favor seasonally flooded areas, at least in areas where the two species overlap. Mouse-colored Antshrikes also seem to join mixed-species flocks less frequently than Plain-winged Antshrikes; instead, pairs or lone individuals feed anywhere from close to the ground to the subcanopy, searching for insects, spiders, and other arthropods.

13–14 cm; 17–20 g. Male is grey above, crown faintly barred darker, concealed white interscapular patch; wings dark yellowish-brown (more rufous in E), wing-coverts greyer, tipped buffy white; tail brownish-black and grey, tipped white; underparts paler, especially on throat and belly, central belly often white; iris grey or, often, brown. Female has forehead and crown dull rufous-brown, upperparts more olive-brown, wings brown (more rufous in E), wing-coverts and wings tipped and edged drab buffy white; tail warm dark brown, outer rectrices thinly tipped whitish; underparts pale grey, tinged yellowish-brown on breast, sides and crissum, olive on flanks. Race <em>cayennensis</em> male has wing colour more reddish-brown than nominate; canipennis male has wings and wing-coverts grey, tipped and edged greyish-white, covert tips forming thin line, iris grey.

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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.

Mid-storey of lowland evergreen forest, to 1000 m; locally up to 1300 m in Venezuelan tepuis. Very much a bird of terra firme forest and forest borders; unlike T. schistaceus, not usually found in seasonally flooded forest. Most common in the sandy-soil forests of the Guianan region.

Presumed resident throughout range.

Little published. Feeds on variety of insects , especially katydids (Tettigoniidae) and grasshoppers (Acrididae), beetles (Coleoptera), bugs (Hemiptera), and adult and larval lepidopterans; also spiders and other arthropods. Pairs or individuals forage 2–25 m above ground, most commonly at 10–15 m in habitats with tall canopy, at 3–8 m in other habitats; progresses by hops and short flights, with frequent pauses to scan for prey. Takes prey by perch-gleans, sally-gleans or hover-gleans from all leaf, stem, vine and branch surfaces; perch-gleans with quick, stabbing motions of the bill. Less frequently associated with mixed-species flocks than is T. schistaceus, but occasionally joins understorey flocks of other antbirds, woodcreepers (Dendrocolaptidae) and foliage-gleaners (Furnariidae) as they move through its home range. Rarely recorded attending swarms of army ants (Eciton burchelli).

Loudsong a slightly accelerating series of up to c. 15 similar notes, very like that of T. schistaceus except notes becoming much shorter and descending only slightly in pitch, last 1–2 at higher pitch instead of falling. Call nasal and abrupt; in alarm a flat, raspy whine, or a clear note that becomes a raspy growl; also variable whines and abrupt notes.

Little recorded. Jan, May and Sept in French Guiana, and Aug–Nov in Brazil. Nest a dark-coloured open cup composed of rough black rhizomorphs surrounding branched rootlets, lined with black and brown rhizomorphs, decorated externally with dried leaves and twigs, suspended by rim from horizontal fork (attached to branches by smooth black rhizomorphs) 2–3 m above ground in understorey sapling or bush. Normal clutch 2 eggs, yellowish-white, with tangle of dark chestnut-brown spots, lines and hairlines “concentrated mostly on top third”; both sexes incubate during day. At a nest in Brazil (Manaus), both nestlings were parasitized by, respectively, 16 and 10 fly larvae.

Not globally threatened. Fairly common to common throughout most of its extensive range; less common in W Amazonia. Vast areas of protected suitable habitat exist within its range: examples include Iwokrama Forest Reserve, in Guyana, Yasuní National Park, in Ecuador, Manu National Park and Biosphere Reserve, in Peru, Jaú National Park, in Brazil, and Alto Orinoco-Casiquiare Biosphere Reserve, Caura Forest Reserve and Imataca Forest Reserve and El Dorado, in Venezuela. Somewhat sensitive to selective logging.