803. Aerocephalus agricola stevensi

(803) Acrocephalus agricola stevensi Stuart Baker.
THE PLAINS PADDY-FIELD WARBLER.
Acrocephalus concinens stevensi, Fauna B. I., Birds, 2nd ed. vol. ii, p. 397.
The range of this little Warbler is not yet known and may very probably extend far beyond the plains of Assam, in which only, so far, has it been found breeding.
The recognition of this Reed-Warbler as something new is of considerable interest to Oologists, as it might well have escaped discovery but for its eggs. These were, in 1905, brought in to Stevens, who forwarded them on to me, and it was at once evident that they were probably laid by a small Reed-Warbler different to anything then known. In 1906 Stevens succeeded in obtaining a few more nests and eggs and, with them, some of the parent birds, which proved to be, as we expected, new to science. To be of any use the birds had to be actually shot off their nests, as in April, and even in May, any other bird might quite well have been a migrant on its way to its breeding haunts either in, or beyond, the Himalayas.
Stevens found this Reed-Warbler breeding in great numbers, on the wide grass-covered swamps and inundated banks of rivers in North Lakhimpur ; possibly, also, in the larger grass-covered “churs” or sandbanks actually surrounded by two branches of the river.
Although the birds were so common, the nests were very hard to locate. The cocks, like all their tribe, were in the habit of singing near their nests on the top of tall reeds but, in these huge expanses of grass-land, anyone approaching the nest could be seen from very far off, and the birds retired among the lower reeds long before the nest was reached. Land-marks of any sort were con¬spicuous by their absence, and one extra tall tuft of reeds or grass duplicated by so many hundreds of other tall tufts that it was almost impossible to mark down the singing birds with any certainty. Again, even when marked down, the dead and withered grass of the previous year so matted the new growth that the nests took much finding, and far more were missed than found. As a rule they were built between 2 and 3 feet from the ground, fastened, like those of all Reed-Warblers, to three or four stems of the new grass. Some found by Stevens were very deep in proportion to their size, one of those first sent me measuring 2.1/2 inches in external diameter and nearly 6 inches in depth, with an egg-cavity about 2 by 5 inches. They were made entirely of strips of grass and reed-bark, and none of those I saw had any wool or moss woven into the other material. Neither was there any real lining, though possibly the inner material was rather finer than the outer, and Stevens mentions that in some of his there was a neat lining of finer grass. The nests are neat, compact and well finished off, and very strongly attached to their supports.
The few nests we have seen with eggs were all found in the last week of April or first fortnight of May, except one pair taken on the 26th June.
The full clutch seems to be three. In appearance they are like tiny brown eggs of A. stentoreus amyoe, and it is curious to note how both the large and the small plains-breeding Reed-Warblers lay such brown eggs. The present bird lays eggs the ground-colour of which varies from a pale buffy brown to a quite definite sepia-brown. The markings are blotches, bolder and larger than in those of our other Indian races, running from dark brown to almost black. The secondary blotches are pale sepia-brown or grey, but all eggs give one the impression of being small brown eggs rather than small green eggs, as in A. a. hokroe.
In shape they are broad to fairly long ovals. The texture seems decidedly coarser than in hokroe and the surface is very dull and glossless.
Thirteen eggs average 15.9 x 12.1 mm. : maxima 16.9 x 12.2 and 16.0 x 12.3 mm. ; minima 14.9 x 12.2 and 15.8 x 11.8 mm.

BookTitle: 
The Nidification Of Birds Of The Indian Empire
Reference: 
Baker, Edward Charles Stuart. The nidification of birds of the Indian Empire. Vol. 2. 1933.
Title in Book: 
803. Aerocephalus agricola stevensi
Spp Author: 
Stuart baker.
Book Author: 
Edward Charles Stuart Baker
CatNo: 
803
Year: 
1933
Page No: 
362
Common name: 
Plains Paddy Field Warbler
M_ID: 
23253
M_SN: 
Acrocephalus concinens stevensi
Volume: 
Vol. 2
id: 
13940

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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith