364. Acrocephalus orientalis.
The Eastern Great Reed-Warbler,
Salicaria turdina orientalis, Temm. & Schleg. Faun. Jap., Aves, p. 50, pl. xx B (1850). Acrocephalus orientalis (Temm. & Schleg.), Oates, S. F. iii, p. 337 ; Hume Dav. S. F. vi, p. 338; Hume, Cat. no. 515 bis; Seebohm, Cat. B. M. v, p. 97 ; Oates, S. F. x, p. 213; id. B. B. i, p. 93.
Coloration. Precisely similar to that of A. stentoreus, except that the throat and breast are generally much streaked with brown, and I have hardly ever seen a specimen in which this streaking was entirely absent. In summer the lower plumage becomes paler.
The dimensions are those of A. stentoreus. The bill is said to be smaller and the tail shorter, but I have not found these points of any use in discriminating the two birds. The second primary generally equal to the fourth.
Distribution. This Reed-Warbler occurs plentifully throughout Southern Pegu, from the head of the Pegu Canal down to Rangoon, and probably throughout the whole of Tenasserim, for Davison observed it at Tavoy and Malawun. It is found in Burma, so far as my own observations extend, from the commencement of October to the middle of May. It has occurred in the Andamans. In winter it has a wide range, being found in south-eastern Asia nearly as far as Australia. It summers in North China, Japan, and Eastern Siberia.
This and the preceding species, A. stentoreus, can only be dis¬criminated with certainty when the wings are fully grown and perfect. The differences may appear very trivial, but they are constant, and are associated with a different geographical Distribution. In Pegu the two birds meet; but here A. stentoreus is rare, A. orientalis extremely common. A. arundinaceus, another species, has its own geographical range, being confined almost to Europe and Africa. It differs from the other two in the shape of the wing, the second primary in this bird being as long as the third, or, in other words, reaching to the tip of the wing.