120 D. Piain — Fauna of Narcondam ami Barren Island. [Ai'KlL, 



cent, of the list, are probably deliberate visitants. And though the Sea- 

 Eagle has become a permanent resident and breeds on the spot, perhaps 

 most of the others are still seasonal visitants and nothing more. This is 

 certainly the case with the Fruit-Pigeons, two of which, Carpophaga 

 bicolor and Galoenas nicobarica come annually from the Nicobars or from 

 Malaya; the third, Carpophaga cenea, may come from Malaya or from 

 Indo-China. Equally is this the case with Pond-Heron, which is a visit- 

 ant from India, and it may be the case with the Sand-Plover and the 

 Sand-Piper which are, in all probability, visitants from the north, and 

 with the Snowy-Tern which is probably a visitant from the south. 

 Perhaps the Blue Reef- Heron, though probably at first a deliberate 

 immigrant, is now, like the Sea-Eagle, a permanent resident. 



The Rock-Swiftlet and the Small King-fisher may either have come 

 deliberately or may have been driven by stress of weather to the islands. 

 The former is now certainly, the latter is probably, a permanent resi- 

 dent. The Swiftlet, if driven here involuntarily, must have been an 

 immigrant under the influence of the south-west monsoon, the King- 

 fisher may have reached the island under the influence of either the 

 south-west or the north-east monsoon. 



The Water-Hen may also have been driven here involuntarily, 

 but is quite as likely to be a deliberate, though an inadvertent, immi- 

 grant. In either case it has probably come from the Andamans, whence 

 also the large Corby has certainly come ; the latter has probably, how- 

 ever, not come deliberately but has been driven by stress of weather. 



The Paroquet and the Sunbird, the Koel and the Bulbul are pro- 

 bably all involuntary immigrants, the two former under the influence 

 of the south-west, the two latter under the influence of either monsoon. 



The most interesting bird of the list is the Narcondam Hornbill, 

 not merely because it is endemic in that island, — pointing to its arrival 

 there being an event of very considerable antiquity since it has had time 

 to develope peculiarities that appear to entitle it to specific rank, and 

 indicating moreover that the event is one which 1ms recurred very in- 

 frequently, if at all — but because, there being no Hornbills in the 

 Andaman group proper, whence birds driven by the south-west mon- 

 soon must have been derived, we are led to conclude that it owes its 

 presence in the island to the influence of the usually weaker north-east 

 monsoon. 



The probabilities of the case are more compactly indicated in the 

 subjoined table. 



