106 PERCY SLADEN TRUST EXPEDITION. 
Australian; Turtur and Tinnunculus are useless for our purpose; Scops rutilus is a 
subspecies of magicus and is certainly Indo-Malayan or Moluccan, but the genus is also 
African and of no use; and, lastly, Gymnoscops insularis is at best a race of Strix 
Jlammea, which is cosmopolitan. 
Including the herons, we find the following to be western or African: Foudia in its 
genus, and Bubulcus, Butorides, Cinnyris, Zosterops, and Pratincola in their species. 
Kastern or Indo-Malayan would be in species Pal@ornis and Scops, and in genera 
Copsychus, Hypsipetes, Erythrena, and the parrots Necropsittacus, Lophopsittacus, 
Coracopsis, and Mascarinus. 
The ultimate result of this investigation is rather startling. African and Indo-Malayan 
influences seem to balance, but it so happens that (1) the western immigrants are all 
birds of poor flight, either bitterns, which do not make long voyages, or small birds like 
the weavers, sunbirds, and girdle-eyes, all of which have come from the nearest available 
land, ¢.e. Africa and Madagascar, by the natural island bridges, and (2) the eastern 
immigrants are all birds of good flight with no tiny forms amongst them. Copsychus 
and Hypsipetes fly well, as do parrots, pigeons, and owls, though the latter perhaps may 
be ruled out as belonging to an indifferent genus (although its species is eastern). 
Finally, it is interesting to observe that parrots and pigeons must be regarded as 
ancient groups, while Cénnyris, Zosterops, and Foudia are as certainly of very recent 
date. One parrot, Lophopsittacus, extinct now, is supposed to have been flightless ; in 
this respect it has parallels in the extinct dodo and solitaire and in tlie flightless rail, 
Erythromachus. 
Systematic List f. 
1. Passer domesticus. Sparrow. 
Found around habitations in all the islands visited. 
2. Crithagra chrysopyga. 
A small finch intentionally carried to Desroches, Amirantes, and now found wild all 
over the island. 
3. Foudia madagascar. Weaver. 
This little weaver is found in all the inhabited islands or groups we visited, except. 
Cargados Carajos, feeding on scraps of coconuts, &c. It must be regarded every- 
where as an intentional introduction of man. 
4, *Hirundo rustica. Swallow. 
5. *Hirundo urbica. Martin. 
Isolated birds belonging to two species of Hésundo, probably the above, were seen 
flying about the different atolls of the Chagos from May to July. 
+ The names employed throughout are those of the British Museum Catalogues, See also ‘The Fauna of British 
India; Aves,’ by W. T. Blanford. 
* The names of birds with an asterisk prefixed as above were species observed by the expedition, but specimens 
were not brought home, 
_ 
