184 TALKS ABOUT BIRDS 



they secrete the gummy nest-material them- 

 selves ; in fact, it is only their saliva. All 

 swifts have very gummy mouths, and glue 

 the materials of their nests together, and this 

 particular kind simply makes the nest entirely 

 of this mouth-gum. It is a little bird, of dark 

 dull colour, and not so big as our sand- 

 martin ; but as the product it gives is so 

 esteemed, the places where it breeds are 

 reckoned good property, and the nests are 

 carefully collected. Care is taken not to 

 work the birds too hard, and exhaust them, 

 for, of course, to get a clean first-quality nest, 

 the first one they make must be taken, so that 

 the birds have to make another in which to 

 rear their brood. Fortunately they are very 

 common where they do nest, inhabiting caves 

 in many thousands. A nearly related kind 

 has taken to building in European houses in 

 the Andaman Islands, and I have seen them 

 there gumming their nests on the wall ; but 

 unfortunately this sort mixes the saliva with 

 moss, so that the nest is of no use for soup- 

 making ! 



Some other East Indian swifts, the tree- 

 swifts, also build a very curious nest. The 



