FRYER— FORMATION OF ALDABRA, ETC. 419 



A drongo (Buchanga aldabrana) is not uncommon, especially on Main Island. It 

 is a glossy black bird, the size of a thrush, with a powerful beak and long forked tail : 

 it is very pugnacious and attacks any frigate or crow (Corvus scaptdaris) which approaches 

 near its perch. 



A cardinal (Foudia aldabrana) is common round the settlement : it differs from 

 F. madagascar in being larger and of a brighter red. 



A beautiful species of sun-bird (Cinnyris aldabrensis) haunts the edge of the man- 

 grove swamp : the male is velvet black, with a wonderful green iridescent gorget and, 

 when hovering in the sun, is a most striking sight. 



The remaining land birds consist of a "white-eye" (Zosterops aldabrensis), a little 

 green bird with habits like a warbler, a bulbul [Ixocincla (Hysipetes) rostrata], a small 

 kestrel {Tinnunculus newtoni), and a small goat-sucker (Caprimvlgus parvulus, sp. V), the 

 last being very scarce. 



Considering the land birds as a whole it will be seen that no land connection is 

 necessary to explain their presence on Aldabra, for even the most flightless, the rail, can 

 still fly and no doubt was once easily able to establish itself over the whole Madagascar 

 region. The birds are all closely related to Malagasy forms and their origin is thus 

 doubtless indicated, for isolation and new conditions will amply account for the slight 

 differences which exist. 



It is impossible to give any complete account of the littoral and marine birds. A few 

 of the more important may be mentioned, most striking of which are undoubtedly the 

 frigate birds, Frigata aquila and F. minor. These birds are present in countless numbers 

 all the year round. Camp Frigate takes its name from the enormous breeding place (of 

 both species) situated there, while another exists on Picard. The whole coast of Malabar 

 Island is often patrolled by a long line of frigates, and there is no part of Aldabra in which 

 these birds are not always in sight. They live almost entirely as parasites on the gannets 

 (chiefly S. leucogaster), which also exist on the atoll in very great numbers. Each gannet 

 on returning from fishing has to run the gauntlet of two or three frigates, which are 

 usually successful in bullying it into disgorging its last meal. Considering this perpetual 

 enmity it is curious that the two birds should frequently nest side by side. In addition 

 to the fish looted from the gannets, frigates are very fond of young turtles newly hatched, 

 and the damage caused by this propensity is very large ; they were rarely seen to fish for 

 themselves and never to plunge into the water. Towards evening there is a considerable 

 flight back to Aldabra of the birds, which have followed the gnu nets to sea. They roost 

 along the lagoon fringe of the mangrove swamp, their position when asleep being very 

 curious, for their heads are allowed to fall loosely on their breasts. 



The flight of the frigate is marvellous, and a sight never to be forgotten is that 

 of a column of the birds wheeling round on motionless wings, the lowest individuals within 

 shot and the highest only to be discovered by the aid of glasses. This however is 

 a subject which has often been written on, and the other habits of the frigate have only 

 been set forth at some length as they appear to differ somewhat from those previously 

 recorded (cf. Camb. Nat. Hist. Birds). 



Of other resident aquatic birds the flamingoes (Phoeniconaias minor) with their 

 brilliant plumage and goose-like cry are sure to strike the attention of an observer. 



