(798) Acrocephalus bistrigiceps.
Acrocephalus bistrigiceps Swinh., Ibis, 1860, p. 51 (China); Blanf. & Oates, i, p. 358.
Vernacular names. None recorded.
Description. Upper plumage olive-brown, tinged with rufous, especially on the rump and upper tail-coverts; wings and tail brown, edged with pale olive-brown; a broad supercilium from nostril to nape pale fulvous and above this a short broad streak of black ; lores and a line through the eye dark brown ; ear-coverts and sides of the neck like the back but paler and brighter ; a ring of pale fulvous feathers round the eye; below pale buff, darkest on flanks, vent and under tail-coverts, albescent on centre of abdomen, chin and throat.
Colours of soft parts. Irides yellow-brown to dark brown; bill above horny-brown to blackish brown, commissure and lower mandible yellowish ; feet fleshy-yellow to horny-brown.
Measurements. Wing 52 to 56 mm.; tail 50 to 55 mm.; tarsus .21 to 22 mm.; culmen 11.5 to 12 mm.
The first primary is comparatively large, measuring about 15 mm. The second primary is equal to the sixth or between sixth and seventh.
After the Autumn moult the upper plumage is a bright russet-brown and the lower plumage a deeper buff.
Distribution. Schrenck's Reed-Warbler breeds, in Japan and Eastern Siberia, possibly also in the North of China ; in Winter it is found throughout the South of China and is common as far West as Siam, the Chin and Kachin Hills and South Burma, straggling very rarely into South Assam.
Nidification. This little Reed-Warbler breeds in great numbers in Japan, making a typical, deep, cup-shaped nest of grass, attached to reed or grass steins in swampy land or on the edges of lakes, waterways, etc. It lays four or live eggs. The groundcolour is a pale yellowish, greyish or greenish white but this is almost obliterated by innumerable freckles and small blotches of light brown with others underlying of pale grey and neutral tint. In many eggs the marks are practically confluent and appear to be wholly a light greenish brown. A few eggs have a hair-line at the larger end in addition to the other markings. In shape they are a short blunt oval. Fifty eggs average 16.2 x 12.6 mm.: the maxima are 17.4 x 12.7 and 17.0 x 13.4 mm.; minima 14.6 x 12.2 mm.
Habits. Those of the genus. According to La Touche and Styan, it has a rather pretty little song as well as the usual harsh notes of all Reed-Warblers. Alan Owston in a letter to me writes that it is such a noisy little bird and " sings so continuously close to its nest that the latter is very easy to find. Directly the bird .sees it is observed it drops down low amongst the reeds but if one is silent and motionless it soon creeps up again to the tops of the reeds and reiterates its jarring little notes."