Fan-tailed Grassbird Catriscus brevirostris Scientific name definitions

16–17 cm; 14–17 g. Distinctive grassbird with disproportionately small head and bill enhanced by flat crown, and relatively massive rear body and strongly graduated broad tail, long loose uppertail-coverts reaching half-way down tail; wings relatively short and broad. Nominate race has head and upperparts greyish-brown, becoming buffy or reddish-brown on mantle, back and scapulars; rump darker brown, becoming almost blackish-brown on uppertail-coverts; tail blackish-brown, each feather pale-tipped (this visible only from below, because shorter rectrices concealed by longer ones), central tail feathers with very weak barring (rather like fault-barring); flight-feathers dark brown with sandy edges, upperwing-coverts greyish-brown; whitish below, becoming buffy on breast side, flanks and ventral region, undertail-coverts (long and loose, as above) blackish with pale scaling (some birds show less blackish than others); underwing-coverts buffy white; iris dull brown; bill dark horn to blackish, pale lower mandible; legs pale fleshy-grey. Distinguished from very similar S. platyurus by rather smaller size (male wing 60–63 mm, against 63–72 mm), fainter barring on tail, lack of indistinct barring on upperparts. Sexes similar. Juvenile has head and upperparts more evenly reddish-brown, underparts washed yellow, and tail less clumsily long and less broad (can thus give remarkably different impression from that of adult). Race alexinae is darker, more olive-brown (less reddish-brown), above than nominate, and lacks warm buff wash on flanks.

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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.

Damp upland grassland near streams, rivers or lakes, particularly with tall rank grasses; also sedge meadows and grassy and bushy mountain slopes. Chiefly between 1000 m and 2150 m, but as low as 600 m in E Zaire; in S of range a seasonal visitor above 1000 m, descending as low as 350 m in Zimbabwe.

Resident over most of range, but skulking nature outside breeding season makes true assessment difficult. In S, known to be a breeding visitor in austral summer to highlands above 1000 m. In Zimbabwe, arrives on breeding grounds from early Nov to Dec and departs in early Apr, but extent of local rains an important factor in timings; in some seasons may be present in highlands until late May.

Poorly studied. Feeds on small invertebrates; small beetles (Coleoptera), grasshoppers (Orthoptera) and hairless caterpillars documented. Generally solitary and (unless displaying) skulking. Forages on the ground, slipping through dense grass in rodent-like manner. If flushed, flies low, with droopy tail, as though top-heavy, and drops back into cover. Most active in early morning and, to lesser extent, in evening; in early-morning mist or drizzle will perch up on grass heads, fences or even telegraph wires, looking forlorn, as if seeking to avoid wet grass.

Song, from perch on large head of grass or in distinctive song flight, a weak but surprisingly far-carrying, almost metallic, ringing “sweep” or similar note, repeated 2–4 times at intervals of 1·6–1·8 seconds (note has also been transcribed as “tseenk”, “tch”, “peee” etc.); whirring wing sound in descent phase of flight. Calls include trisyllabic “jur-jur-jur”, sharp “prit-rit”, harsh “chick”, rapid harsh rattle and wheezy “tzzzt-tzzt”.

Birds in breeding condition in Jul in Sierra Leone, Jul and Aug in W Kenya, Mar–Oct in E DRCongo, Jan and Feb in Zambia, Dec–Mar in Malawi, Nov–Feb in Zimbabwe and Dec–Mar in South Africa. In distinctive song flight, slowly circles or spirals up to c. 25 m above ground, jerking tail up and down, beating wings with surprising rapidity (producing whirring sound), before planing down on set wings to perch on grass head or disappear into grasses. Nest extremely well concealed, a bulky bowl of coarse dry grasses, only loosely woven into deep hollow of a dry grass tuft, typically sited 5–30 cm above water or wet ground. Clutch 2–3 eggs, laid at 24-hour intervals; no information on incubation and nestling periods; apparently both sexes feed young.

Not globally threatened. Fairly common, but rather local. At N limits of extensive range, distribution is fragmented and a number of populations poorly known; some of these (in Sierra Leone, Guinea, Cameroon, Gabon, Sudan and Ethiopia) could well be under threat from overgrazing and general habitat degradation. Very sparsely recorded in S Sudan (only two records) and in Ethiopia. Even in regions where this species is well known there are considerable fluctuations in numbers, depending on local grassland conditions; populations at low level in dry years. Considered to be decreasing, although not yet classed as “endangered”, in South Africa, where habitats threatened by commercial afforestation, damming and consequent flooding of peripheral marshlands, and trampling of grassland by cattle.