796. Aeroeephalus stentoreus amyse

(796) Acrocephalus stentoreus amyae Stuart Baker.
THE ASSAM GREAT REED-WARBLER.
Acrocephalus stentoreus amyoe, Fauna B. I., Birds, 2nd ed. vol. ii. p. 390.
This race of the Great, or Clamorous, Reed-Warbler breeds probably all along the Himalayan sub-terai on the West from at least Bahraich as far as Eastern Assam. Birds sent me as breeding in the Inli Lake in the Shan States were, I believe, of yet another and bigger race, though the skins were not sufficiently perfect to enable me to decide with certainty.
The first specimen I received, through Wickham, I identified as of this race, but further specimens received direct from Mr. Livesey made me very doubtful as to the correctness of this determination. Traces of streaks on the lower plumage of one specimen and an apparently more rounded wing show a very close approach to Acrocephalus arundinaceus orientalis, but perfect specimens are still wanted.
The first to record this bird’s nest and eggs was Whymper, who writes (Journ. Bomb. Nat. Hist. Soc. vol. xviii, p. 495, 1908):— “While on a large jhil in the Bahraich. District on August 14th I was much surprised to hear the unmistakable harsh note of Acrocephalus stentoreus sounding from several directions and, on searching round, wherever the birds were calling, several nests with young and, at last, three nests with fresh eggs were discovered and the birds secured. The nests were all placed rather low down, within three feet of the water, in more or less detached clumps of reeds inside very dense reed-beds, and seemed to be somewhat smaller and made of finer (or less coarse) grasses than those I have seen in Kashmir. The birds, too, are somewhat smaller.”
Later Whymper took other nests of this bird, containing two and three eggs respectively, on the 10th and 14th August, which he sent to me.
The year previous (1906), however, Stevens, in Assam, had also taken the eggs of a Reed-Warbler which he described to me as small dark specimens of A. s. brunnescens. I asked him to send them to me and duly received three clutches of two, four and two eggs, taken in the last week of April and the 1st of May.
These at once showed me that the bird which laid them was not the Kashmir brunnescens, as the eggs were much too small and were darker, duller and browner in general tone. Specimens of the birds were then obtained which proved to be of this new race. The place where Stevens found these birds breeding was round Hessamara, in North Lakhimpur. They were numerous but were nesting in such huge swamps, covered with endless beds of elephant-grass, reeds and long grass, that it was impossible to obtain many nests, The nests, of which Stevens sent me three and kept others for himself, are like those made by the Kashmir bird but are decidedly smaller, about 3 inches or less in outward diameter and about
4 inches in depth, the egg-cavity being about half an inch less each way. They are also neater nests and made of finer stems and strips rather than the ragged blades which brunnescens usually makes use of. Again, they are far more neatly fixed to the reed- stems, the materials passing round the stems and then being neatly wound into the fabric of the walls, whereas brunnescens leaves many of the ends sticking out everywhere, while the stems are very loosely bound in as a rule with most of the materials.
A nest found by myself later in Dimaji in May, with four hard-set eggs, was exactly similar. The birds were breeding in elephant-grass, 8 to 10 feet high, and this was the only nest we saw, as the ground was impossible to work. We saw some young birds able to fly and, I think, most eggs had hatched.
In the years 1918 onwards F. Field was able to work over some of the swamps in Oudh and was successful three years running in obtaining nests with eggs, of which he was good enough to send me some, these agreeing exactly with those found by Whymper and Stevens. The birds again proved to be of the small dark sub-montane race.
In the United Provinces the breeding season seems to be after the rains break, in the middle of June, until August ; that is to say, the birds do not breed during the season of great drought but wait until the swamps begin to fill. In Assam they breed in April and May, but here there are always ample swamp-lands, well flooded and with never-ending beds of reeds which stand, year in year out, a tangled mass of old and new growth.
The full complement of eggs is three or four and these, in appear¬ance, are like those of A. s. brunnescens but are duller and browner and. as I have already said, much smaller.
Thirty eggs average 20.6 x 15.0 mm. : maxima 23.0 x 16.3 mm. (possibly a double-yolked egg, taken by Whymper) ; minima 18.3 x 15.3 and 19.2 x 14.1 mm.