50 A NATURALIST IN CELEBES ch. hi 



space of time. Contenting myself, however, with a dozen 

 nests and eggs, and two or three specimens of the birds 

 for future identification, I was glad to get away from 

 the stifling atmosphere of the cave, and the heart-rending 

 shrieks of the terrified parents, into the purer air outside. 

 I found that the nests were of a very inferior quality — from 

 a commercial point of view — that is to say, they were com- 

 posed of a very large proportion of vegetable fibre and 

 feathers, and a very small proportion of the consolidated 

 saliva of the bird. These nests were in bygone times of 

 some value, and the cave used to be the ' property ' of the 

 Eajah of Manado. Of recent years, however, there has 

 been some dispute as to the ownership of this cave, and I 

 believe that at the present time no one actually claims the 

 sole right to take the nests. As the approach to the cave 

 is not without danger, and the Chinese in Manado now 

 import large quantities of the nests from Borneo and the 

 Philippines, where they can be obtained of very much 

 better quality, the value of this cave has very much 

 diminished, and I believe it is now worth very little. At 

 any rate, I tried to persuade myself that I had not been 

 guilty of committing the heinous crime of poaching on 

 another man's preserves. 



There has been a considerable discussion as to the way 

 in which these little birds manufacture their nests ; but 

 there can be no doubt now that they are formed by the 

 consolidation of the mucous secretion of the salivary glands. 

 The belief that the little bird makes them by the mastica- 

 tion of a particular kind of sea-weed is now known to be 

 erroneous. The natives, however, have an explanation of 

 the formation of this material which is novel, if not 

 plausible, They pointed out to me that in July and August, 

 when the birds are building, the waves of the sea are fre- 

 quently capped with crests of foam. Thousands of the 



