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Show 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 Borneo1. [Received February 2, 1888.] The increasing attention to valuable products of trade in new countries has led m e to prepare the following notes on the Birds'- nest Caves of Northern Borneo gathered during a residence of nearly five years in that country. The number of caves that are known to be in existence up to date are referred to in tbe 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 saliva2. The nests have been carefully analyzed by chemical experts, and no traces of vegetable 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 1 In the discussion which followed the reading of this paper, Mr. W . H. Treacher (late Governor of British North Borneo) pointed out, in reference to Mr. Daly's explanation of the differences in the 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 found in the inland caves, and the former a large bird, of livelier colour, with a white 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 caves 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. 2 See Mr. H. Pryer's paper on this subject, P. Z. S. 1884, p.' 532 and the accompanying footnote. |