VERTEBRATE FAUNA OF HODTMAN's ABROLHOS. 473 



from one group to another. It is a great pity that it is not known how this 

 exodus took place, nor for certain what was its cause. The cutting down of 

 the mangroves, suggested by Campbell, has not taken place, as I believe 

 they only furnish very inferior timber for burning. Prof. Dakin tells me 

 that some years ago the soil of the mangrove swamp was dug out from 

 the roots of the trees, being almost pure guano, and probably this disturbed 

 the birds so much that they removed to their new home. 



Wooded Island, in spite of its name, has not so many mangroves as 

 Pelsart Island, and almost every tree is covered by their nests. Their 

 numbers at the present time, however, cannot be anything like what they were 

 30 years ago, as they are certainly far fewer than either the Sooty Terns 

 or the Noddies. Moreover, there is every reason to fear that they are still 

 decreasing, for every occupied nest on the trees there are several old ones, 

 and Prof. Dakin tells me that on his last visit, in 1915, he thought there 

 were fewer nests occupied than when I was with him in 1013. I can 

 suggest no reason for this decline ; there are no obvious enemies of these 

 birds on Wooded Island, but it appears that the guano accumulated below 

 their nests on Wooded Island is likely to be worked before long, when 

 presumably they will have to make another move. This could not have 

 been long delayed in any case, as the accumulation of the guano round the 

 roots of the mangroves is rapidly killing the trees, and it is unlikely that 

 the birds would continue to nest on the boughs of the dead trees. It is to be 

 hoped that a change to another island may lead to an increase in their 

 numbers, otherwise I fear they must be regarded as the last remnant of a 

 dwindling race. 



Bruchigavia NOV^aoLLANDi^E longirostris (Masters). Silver Gull. 



These birds occur throughout the group. Small colonies were found 

 nesting on West Wallaby Island, an islet off Rat Island, Wooded Island, and 

 Pelsart Island. A few eggs were still not hatched, and young birds were 

 met with in every stage from newly hatched to fully fledged. 



Gabianus pacificus georgii (King). Pacific Gull. 



Not so plentiful as the Silver Gull, but distributed over all the islands. 

 No eggs were found, but young birds half-grown or fully fledged were noted 

 on West Wallaby Island, Long Island, Wooded Island, and Pelsart Island. 

 Mr. Lipfert found fresh eggs on an island off Rat Island on October 7, 1891. 



Charadriiformes. 



AEENAKIIDiE. 



Arknaria interpres oahuensis (Bloxliam). Turnstone. 



A very common summer visitor, found round the shore on all the is'ands. 



LINN, JOURN. ZOOLOGY, VOL. XXXIV. 35 



