COLLOCALIA. 31 



from its original bed, has left a slit in the side of the hill, blocked 

 at one end, some 40 yards loug, 30 feet high, and of an average 

 width of about 3 feet. The mouth of the cave is much darkened 

 with stones and shrubs, so that 10 yards from the entrance, without 

 a light of some sort, one gets a very hazy idea of the surroundings. 

 AVe had a candle, and after going the whole length of the cave we 

 set to work counting the nests of the Swifts. This was no easy 

 job ; however, with a little trouble we made out that there were 

 fully 250 nests in the cave, of which two in every three were 

 occupied by eggs or young. While all this was going on, the old 

 birds were in a great state of excitement, and occasionally one, 

 more courageous than the rest, would dash at the candle and, 

 putting it out, leave us to grope about for the matches. We took 

 three or four nests, and altogether a dozen eggs. Of these two 

 only were hard-set, the rest being perfectly fresh ; and as we took 

 only solitary eggs, it would appear that this Swift occasionally lays 

 but one egg, though far more frequently two, and never, I believe, 

 more. As I hope my brother will send you specimens of eggs and 

 nests, I need only say in passing that the nests are pretty solid 

 cups with a shallow cavity, composed principally of moss and the 

 feathers of the bird, cemented to the rock and neatly lined with 

 threads of the peculiar isinglass-like substance excreted by the 

 bird. The eggs are pure white, smooth, and slightly glossy : and 

 of those taken the measurements ranged from 0'81 to 0-91 in 

 length, and from 0-52 to 0'59 inch in breadth, averaging 0-85 

 by 0-55. 



" This accomplished, we had to secure some of the old birds. 

 After expending all our small stock of cartridges we had only t\vo 

 birds to show, and these on dissection proved to be males. One 

 bird was evidently in the breeding-stage and the other not ; and I 

 may here note that the breeding one had a very highly-developed 

 gland beneath the chin, containing a sticky creamy substance, 

 which was no doubt the same as that used to fasten the nest to 

 the rock ; this bird also, when shot, had a piece of moss in its 

 (>, so that one may fairly conjecture it was still building. The 

 other bird had no trace of the gland, at least so far as I could make 

 out without the aid of a microscope. My brother will also send you 

 with the nests and eggs a sample of the guano which was thickly 

 spread over the floor and walls of the cave. This appears to be com- 

 posed principally of the undigested portions of the birds" food, with 

 some proportion of soluble ammoniacal matter, which has a rather 

 disagreeable smell." 



Colonel Legge thus describes the breeding-habits of this Swift 

 in Ceylon : " The breeding-season of this little Swiftlet in Ceylon 

 lasts from March until June. It nests in large colonies in various 

 rav'-s in the hills and mountains of the central and southern parts 

 of the island. Many of these are known from seeing the birds 

 haunt the vicinity of certain precipitous hills ; but few have been 

 visited and examined on account of the general inaccessibility of 

 these resorts. Among those which are known are two situated on 



