THE ESCULENT SWALLOW. BIRDS. THE ESCULENT SWALLOW. 



285 



species engaged in the production of the edible nests 

 will be found to correspond with the description of the 

 illustrious Swede ; there being several concurrent testi- 

 monies in the works of the older travellers and natu- 

 ralists, to the effect that the Esculent Swallow has 

 white spots on the tail feathers. Should this prove 

 correct, there will be at least three known species of 

 these birds, namely 



CoUoculia esenlenta of Linnseus ; 



CoUoealia fuciphuga of Thunberg (since described by Mr. 



G. R. Gray as C. nidifica, on the ground that Thun- 



berg's name is erroneous) ; and 

 CoUoealia Linctii of Horsfield and Moore, a species very 



nearly allied to C. fuciphaga. 



Although, as already stated, Thunberg had adopted 

 the notion that these Swifts procured the materials oi' 

 their nests from the sea-weeds cast upon the shore by 

 the waves, and other writers maintained a somewhat 

 similar opinion, namely, that the glutinous matter 

 was derived from the spawn of fishes or the bodies 

 of mollusca, the Rev. J. Hooyman published in 1781 

 a paper, in which he completely disproves these 

 views, and approaches very nearly to the true solu- 

 tion of the problem. He declares that the food of 

 the birds consists of insects a statement which has 

 been confirmed by subsequent observations. He de- 

 scribes the habits of the birds as very similar to those 

 of the other Swifts; they resort during the day to 

 marshes, inland lakes, and plains, over which they 

 hover in pursuit of the insects which abound in such 

 situations; and it is difficult to suppose that those 

 numerous individuals which inhabit the interior of such 

 large islands as Java and Sumatra would undertake 

 a journey to the sea-coast and back in search of the 

 materials for their nests. Mr. Hooyman's idea of the 

 mode in which the glutinous material of the nest is 

 procured is, that it is elaborated from the food of the 

 bird, by a peculiar organic effort resembling secretion. 

 In this it will be seen that he was not far from the 

 truth, for Sir Everard Home and Mr. Blyth both state, 

 that the glutinous matter is undoubtedly a secretion 

 from the enormously-developed salivary glands, and 

 chemical analysis of the nests has confirmed this 

 conclusion. 



We have stated above that the Collocalice producing 

 edible nests are found in great numbers both on the 

 Indian continent and in the islands ; but it is principally 

 in Java that any information as to the natural history of 

 the birds and the mode of collecting the nests has been 

 obtained. This island appears to be peculiarly adapted 

 for the dwelling-place of these birds, which congregate 

 in large nocks in caverns and fissures of the rocks, and 

 build their nests upon the walls of these. Both in the 

 interior and on the coast extensive hollows are formed 

 abundantly in the rocks, probably caused to a consider- 

 able extent by the volcanic action to which the island 

 is so subject. Here the Swifts swarm in vast flocks, and 

 the management of the nests, especially in the caverns 

 of the southern shore of the island, is laid down by 

 regulations established by the government. So well 

 is this singular harvest regulated, and so well has 

 experience taught its managers .the conditions under 

 which it is to be realized, that the average quantity of 



nests to be expected from each cave may be estimated 

 before the season for gathering them, with remarkable 

 accuracy. 



The collection of the nests is undertaken in Java at 

 three periods in the year. The principal harvest is 

 gathered in the month of October, after the birds have 

 been left undisturbed for about six months ; the other 

 two gatherings are in December and March, so that 

 there are two intervals of three, and one of six months, 

 between the gatherings. The shorter periods scarcely 

 allow the birds time to build their nests and bring their 

 progeny to mattirity, so that both in December and 

 March great numbers of young birds are necessarily 

 destroyed ; on the other hand, the nests obtained at 

 these gatherings are of superior quality, clean and 

 white, and very free from any extraneous matters. 

 During the longer interval of six months the birds are 

 enabled to rear two broods ; thus the quantity of nests 

 becomes very large, and the maintenance of a sufficient 

 number of the birds is provided for. In collecting the 

 nests, various contrivances in the shape of ladders 

 and scaffolding are necessary; and notwithstanding 

 these aids, the gatherers appear to be exposed to con- 

 siderable risk. 



The number of nests collected in Java is very great, 

 the quantity passing annually through the market of 

 Batavia on its way to China being estimated by both 

 Raffles and Craufurd at two hundred peculs, or two 

 hundred and fifty hundredweights ; but this is nothing 

 in comparison with the Sooloo Archipelago, which 

 produces no less than five hxmdred and thirty peculs. 

 The total value of the edible birds' nests imported into 

 China is said to be 1,263,570 Spanish dollars, or 

 284,290 sterling. This, however, can give us but an 

 imperfect clue to the actual quantity of this article of. 

 luxury which finds its way to the Chinese markets ; 

 the price paid for the nests varying greatly according 

 to the quality of the different samples. Thus the best 

 and purest sorts fetch 3500 Spanish dollars per pecul, 

 or about 5 10s. per pound ; the second quality will 

 not bring more than 2800 dollars ; and the third only 

 fetches about 1600 dollars. These prices will give 

 some notion of the way in which these birds' nests are 

 prized in China, but they still only indicate the value 

 at the place of importation. This value increases to a 

 very considerable extent as the delicacies are conveyed 

 away from the coast, and we are told that in some 

 parts of China, a catty, or about one pound and a 

 quarter of these nests, has fetched no less than 40 

 Spanish dollars, equivalent to 9 sterling. 



FAMILY III. HIRUNDINID^E. 



In this family, which includes the well-known species 

 of true Swallows, we meet with characters very similar 

 to those presented by the Swifts, which form the pre- 

 ceding family. The differential characters of these 

 two groups were, to a certain extent, indicated under 

 the head of the Cypselidse, so that we need not dwell 

 upon them here at any length. In their general form 

 the Swallows closely resemble the Swifts, as they do 

 also in their mode of life ; but their wings are shorter 

 and broader, their nostrils of small or moderate size, 



