1866.] VISCOUNT WALDEN ON BIRDS FROM TENASSERIM. 537 



15. Notes on Birds collected in Tenasserim and in the Anda- 

 man Islands. By Arthur, Viscount Walden, F.L.S., 

 F.Z.S. 



Dr. Sclater has placed in my hands for publication the ornitho- 

 logical portion of a zoological collection which Captain Beavan is en- 

 gaged in making in Tenasserim, and the firstfruits of which he has 

 recently transmitted to this country. With the exception of six 

 species obtained in the Andaman Islands, the specimens sent were 

 collected in the neighbourhood of Moulmein and in the valley of the 

 lower course of the Salween River. The collection is accompanied 

 by some interesting notes of observations made by the collector, most 

 of which, if, indeed, not all, convey new information. These notes I 

 have transcribed in full ; and it is to be hoped that during his stay 

 in the Tenasserim provinces Captain Beavan will continue the useful 

 practice of recording such observations as it is only within the power 

 of the field-naturalist to make. An exhaustive catalogue of the Avi- 

 fauna of the Tenasserim provinces has yet to be compiled. The 

 identity of rarer species with the types from the neighbouring coun- 

 tries has in the majority of cases yet to be determined ; and where 

 differences occur, the degree and nature of the variation have in many 

 instances still to be made known. In nearly all the species the 

 exact limits of their areas of distribution remain a desideratum ; and 

 it is only by means of local collections, such as the one Captain 

 Beavan is now engaged in making, that any progress in these branches 

 of knowledge can become possible. Mr. Blyth, it is true, has 

 amassed a large number of facts bearing on these subjects ; but they 

 are scattered through so many papers and different periodicals, that, 

 until they are brought together and systematically arranged, much 

 time will have to be spent by the student before full benefit can be 

 derived from their undoubted value. In Europe little has been done, 

 chiefly in consecmence of the want of authentic specimens from dif- 

 ferent localities, and sufficiently large series of the specimens sent. 

 As a result of this paucity of local specimens in our museums, or 

 rather in one and the same collection, many species inhabiting the 

 continent of India for instance, remain still bearing titles originally 

 bestowed on forms foreign to that country ; and an absolute iden- 

 tity, as far as these species are concerned, is thus assumed to exist 

 between birds, not migratory, inhabiting regions widely apart. And 

 yet, on comparison being made between actual specimens from distant 

 localities, certain differences are frequently, and in many genera in- 

 variably, discovered, which, whether of specific value in the opinion 

 of some naturalists or not, still seem to go far in showing that ab- 

 solute stability and immutability of specific forms in birds does not 

 exist. 



The numbers and sexes given at the head of each species in this 

 paper are those attached to the specimens by Captain Beavan. I 

 commence with the Tenasserim specimens. 



Proc. Zool. Soc— 1866, No. XXXV. 



