222 A NATURALIST ON DESERT ISLANDS. 



to huQt about for likely spots than we had ; for petrels, 

 owing to their nocturnal habits, nxay be nesting beneath 

 the very rocks upon which one is actually treading, and 

 yet show not the faintest indication of their presence. 



This we well remember having had very patently 

 brought to our notice in the case of another petrel (Pufflnus 

 obscurus), which w^e found in May, 1907, nesting in some 

 honeycombed rocks of coral limestone, on a small islet 

 in the Bermudas. Here, secure from rats and the inter- 

 ference of man, a small colony still held out, descendants, 

 most probably, of that mystic bird which the early colonist 

 called " Cahow," and which in their straits for food they 

 practically exterminated. On this occasion, had it not 

 been for the guidance of Mr. Mowbray, a Bermudan 

 naturahst, I should probably have left the rock under 

 the impression that there was not a bird on it ; for there 

 were none to be seen flying about, and their nests were 

 most difficult to find, even when, as Mr. Mowbray did, 

 one knew of their locality to within a few yards. I took 

 one of these birds for identification, and it is now in my 

 collection. Lieutenant Reid, R.E., in " The Birds of the 

 Bermudas " (The Zoologist, Oct., 1877), relates that he 

 found two nests of this bird in 1874. Since then there has 

 been no record or knowledge of their existence on the 

 Bermudas, until Mr. Mowbray foimd them in 1907 on 

 this small islet. It is interesting to note the following 

 remark Avhich Mr. Reid makes in his account of 

 this bird : "I know of only one instance of a ' Cahow ' 

 being seen on the wing, in the daytime, in Bermudan 

 water." 



The real difficulty of finding petrels on the Hermanos 

 Islands, would be to know just when they breed ; for petrels 

 vary locally in the time of their nesting in the most 

 unaccountable manner ; and as, for the most part, they 

 only visit the land at this time, unless one can hit off their 

 breeding season, there is little chance of finding them 

 *'at home." In this connection, I might state, that whereas 

 in the Bermudas, I found Audubon's petrel nesting and 



