Bats and Swifts 313 



captured and the captors were so very different from any of 

 the animals here dealt with, his account is so interesting that 

 little apology is, I hope, necessary for making the following 

 rather lengthy extract from it. It appears in the Proceedings 

 of the Society for 1885, p. 534, et seq., and refers to 

 observations made in Borneo, in the exploration of caves 

 inhabited by the Swifts, which make the edible nests so 

 much prized by Chinese epicures. He writes 



" At this point I found myself at the mouth of a cave 

 named Simud Putih, i.e. the White Cave. The entrance 

 is about forty feet high by sixty feet wide, and descends 

 very steeply, widening out to a great size, and having a 

 perpendicular unexplored abyss at its furthest point. This 

 cave is used by the nest gatherers as their dwelling-place, 

 and at the entrance are their platforms of sticks, one of 

 which was placed at my disposal by the head man ; it is 

 also the cave by which the great body of the Swifts enter. 

 Immediately outside it is a great circular opening leading 

 sheer down into Simud Itam ; this is one of the two open- 

 ings mentioned as giving light to that cave, and is the 

 entrance most in use by the Bats. As soon as I had un- 

 packed and settled down on my platform, I sallied out to 

 find the material from which the birds make their nests, as 

 my previous experience is that birds do not, as a rule, travel 

 far for the bulk of the material they use. I was speedily 

 successful in my search. It is a fungoid growth which 

 incrusts the rock in damp places, and, when fresh, resembles 

 half-melted gum tragacanth ; outside it is brown, but inside 

 white, and little if any change in its consistency is effected 

 by the bird l ; the inside of the nest is, however, formed by 

 threads of the same substance, which are drawn out of the 

 mouth in a similar way to that of a caterpillar weaving its 

 cocoon. 



1 This was an error, it being now admitted that the nests are formed 

 entirely of mucus secreted by the salivary glands of the birds which when 

 dry looks like isinglass. Our own Swifts glue together the scanty materials 

 of which their nests are formed, with a similar saliva. The birds, which 

 form the edible nests above referred to, belong to the Genus Collocalia, 

 which differs in several respects from that to which our Swifts belong, and in 

 which the development of the salivary glands is especially remarkable. 



