VERTEBRATE FAUNA OE HOtTTMAN's ABROLHOS. 467 



Birds. — Of the 12 land-birds recorded from the Abrolhos, four (Kestrel, 

 Robin, Song-Lark, and Pipit) are certainly only casual visitors, five others 

 (Rail, Crake, Kingfisher, Swallow, and White-eye) are probably visitors 

 from the mainland, though all but the Crake and Kingfisher have been known 

 to breed ; the remaining three are almost certainly residents. 



Of these, the Pigeon and the Quail are found in the Wallaby Group and 

 on North Island, the Scrub-Wren only on the Wallaby Islands. The two 

 latter are subspecifically distinct from the mainland forms. 



Looking now at the different groups of islands we find that West Wallaby 

 Island has two snakes and two slow-worms confined to it, East Wallaby 

 Island has one snake and one rat confined to it, whilst the two Wallaby 

 Islands possess subspecies of a wallaby and a bird peculiar to them. 



The Wallaby Islands, with North Island, possess also one lizard and two 

 birds not found in the other groups, one of the birds being a subspecies 

 peculiar to the group. 



This distribution strongly suggests that the whole land-fauna of the group 

 has been derived from the Wallaby Islands *. One of the chief features 

 of the weather on the Abrolhos is the prevalence during the summer of 

 " southerly busters,''' extremely strong southerly winds. The presence of the 

 two birds on North Island is thus easily accounted for, and it is noteworthy 

 that the one lizard which habitually climbs bushes is the one which has 

 managed to reach that island. Doubtless at times the bushes on the sand-hills 

 which it frequents are blown into the sea, and occasionally reach North Island. 



The fact that the smaller skinks are found on many of the small sandy 

 islets seems to show that the sea is no great barrier to their distribution. 

 Probably their eggs are not damaged by floating in sea-water for some time. 

 The larger Spiny-tailed Skink, Eyernia stokesi, is a favourite food of the Sea- 

 Eagles, and it is possible that individuals may be captured by them on 

 the Wallaby Group and carried to Rat Island, and if one occasionally escaped 

 this would account for their presence on that group. 



A striking feature of the Abrolhos land-fauna is its southern character. 

 Our knowledge of the distribution of animals in Western Australia is 

 perhaps not sufficient to allow us to be dogmatic on the point, but there is 

 eveiy indication that when the islands were peopled from the mainland the 

 fauna of the Geraldton district must have approximated much more than it 

 does now to that of the extreme south- \\ est. The range of Macropus eugenii 

 does not now extend much north of Perth, whilst Epimys fuscipes is only 

 known from the south coast and the islands of the Recherche .Archipelago. 

 Ortygodes varius and Cosmopelia elegans are not recorded from farther north 

 than the Moore River, though it is not improbable that they may occur ; 

 Porzanoidea plumbea is not recorded from north of Perth. 



1 [A discussion ou the origin of the fauna of the Abrolhos I.-lands will be given in the 

 concluding paner of the series. — W. J. Dakin.] 



