Acrocephalus luscinia yamashinae (Takatsukasa)
Nightingale Reed-warbler
Conopoderas yamashinae Takatsukasa, Dobutsu. Zasshi, 43, 1931, p. 485. (Type locality, Pagan.)
Tatare syrinx Oustalet (part), Nouv. Arch. Mus. Hist. Nat. Paris, (3), 7, 1895, p. 210 (Pagan).
Acrocephalus syrinx Hartert (part), Novit. Zool., 5, 1898, p. 58 (Pagan); Seale (part), Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 53 (Pagan).
Acrocephalus stentoreus syrinx Kuroda (part), in Momiyama, Birds Micronesia, 1922, p. 67 (Pagan).
Conopoderas yamashinae, Hand-list Japanese Birds, rev., 1932, p. 177 (Pagan).
Conopoderas luscinia yamashinae Hand-list Japanese Birds, 3d ed., 1942, p. 196 (Pagan).
Acrocephalus luscinia yamashinae Mayr, Birds Southwest Pacific, 1945, p. 294 (Pagan).
Geographic range.—Micronesia: Mariana Islands—Pagan.
Characters.—Resembles A. l. syrinx, but duller and more brownish and less olive-rufous on back, rump and tail; bill shorter and more curved.
Takatsukasa (1931:485) gives the following description: "Upperparts dark olive brown, paler on the lower rump; remiges and rectrices dark olive-brown, margined with brown. Superciliary stripe distinct and buff; chin, throat, breast and abdomen pale brown; ear-coverts, sides of neck, sides of breast and flanks dusty greyish brown, belly and under tail-coverts pale buff. Bill clove brown, legs grey, and iris Van Dyke brown." He continues, "It differs from Conopoderas syrinx of Caroline Islands by its colouration and the shape of the bill, namely in the new form the culmen is more curved and more stout, and the tail is less roundish and nearly square."
Measurements.—Takatsukasa and Yamashina (1931b:485) lists the following measurements: 13 adult males—wing, 75-80; tail, 65-70; culmen, 20-22; 6 adult females—wing, 73-77; tail, 60-65; culmen, 20-22.
Mayr examined seven specimens from Pagan in the Paris Museum. His measurements are: five males—wing, 76-79; tail, 66-69; bill from nostril, 14-14.5; two females—wing, 75, 77; tail, 66, 67; bill from nostril, 14.5, 15.
Remarks.—No specimens have been examined by me. Oustalet (1895:210) was the first to note the difference between the reed-warblers from Pagan and those from Guam and Saipan (A. l. luscinia). He regarded those from Pagan as similar to the population in the Carolines, calling them Tatare syrinx. Hartert, Seale, and Momiyama followed Oustalet in this regard, and it was not until 1931 that the population at Pagan was recognized as distinct, when further collections were made by the Japanese.