108 MR. D. D. DALY ON THE CAVES CONTAINING [Feb. 7, 



5. On the Caves containing Edible Birds'-nests in British 

 North Borneo. By D. D. Daly, Assistant Resident, 

 British North Borneo'. 



[Received February 2, 1888.] 



The increasing attention to valuable products of trade in new 

 countries has led me to prepare the following notes on the Birds'- 

 nest Caves of Northern Borneo gathered durhig a residence of nearly 

 five years in that country. The numl)er of caves that are known to 

 be in existence up to date are referred to in the order of their size, 

 wealth, value, and importance both as regards the quantity and 

 quality of the nests. Many of these mountain-caves have been 

 visited by Europeans since the establishment of British North Borneo 

 as a Colony under Royal Charter in November, 1881 ; but there are 

 a few that are so inaccessible amid inland mountains and among 

 semi-hostile tribes that they have not yet been explored, and are 

 only alluded to from native information. 



The edible nests of the Swift {Collocalia fuciphaga) are valued in 

 China only; to the European palate birds'-nest soup has an insipid 

 taste. 



Many theories, some of them absurd, have been propounded 

 with respect to the mode of formation of the nests ; it may, however, 

 be laid down as indisputably proved by experts that the nests are 

 made by the Swifts of their own inspissated saliva^. The nests have 

 been carefully analyzed by chemical experts, and no traces of vege- 

 table matter have been discovered. The thready mucus is worked 

 up by the Swift from the salivary glands in its neck. 



The strings of mucus are plainly visible in the nests which I have 

 the pleasure of exhibiting at this meeting, and which were brought 



^ In the discussion which followed the reading of this paper, Mr. W. H. 

 Treacher (hite Governor of British North Boi-neo) pointed out, in reference to 

 Mr. Daly's explanation of the differences in tlie colour and value of the nests, 

 that Sir Hugh Low, writing on Sarawak about 40 years ago, maintained that 

 two distinct varieties of birds formed the white and the black nests respectively, 

 the latter being a smaller dull -coloured bird, generally i'ound in the inland 

 caves, and the former a large bird, of livelier colour, with a wliite belly, and 

 found in the caves near the sea-shore ; and that the natives of whom he had 

 inquired, corroborated Sir Hugh's statement; he also pointed out that the 

 Sigalong caves yielded almost entirely white nests, while those of Madai, close 

 by, were almost all black ones. In the Gomanton series some of the cavea 

 always yielded black nests, and others always white ones, although the nests in 

 all were collected with equal regularity. The Hon. Ralph Abercromby said 

 that when he visited the Gomanton caves the natives showed him three 

 different-sized eggs, and said the largest was the egg always found in the white 

 nests ; he added that a German naturalist, who had resided in Palawan, had, 

 however, given him an explanation similar to Mr. Daly's. 



Mr. Sclater said that only one kind of Swift had been sent to him from 

 Borneo for identification, and that that, as determined by Mr. Sharpe (see 

 P. Z. S. 1886, p. .54), was Collocalia fuciphaga ; he suggested that the Company's 

 officers might easily settle the question by procuring specimens and sending 

 them home for determination, and urged them to adopt this plan. 



' See Mr. H. Fryer's paper on this subject, P. Z. S. 1884, p. 532 and the 

 accompanying footnote. 



