BIRD-NOTES 63 



situated at the base of the pygidium, and after this 

 operation the colours of the beak appear brighter than 

 ever. This is simply due to the fact that the oiling of the 

 beak makes the outer layer more transparent, and con- 

 sequently the underlying pigment shows through more 

 distinctly. If the bird is not in a good state of health, 

 the oil-gland does not secrete properly, and the colours 

 of the beak become much duller. Some time after 

 death the outer horny layer becomes quite opaque and 

 the beak turns to a dirty white, but much of its pris- 

 tine beauty can be restored by the application of a 

 little vaseline or salad oil. Rhinoplax vigil has a small 

 but perfectly solid casque, and the beak of this species 

 is therefore a rather formidable weapon. The use or 

 purpose of the casque in the Hornbills is quite obscure : 

 as it is present in both males and females, it is not a 

 sexual adornment comparable with the tail of the Pea- 

 cock, and it does not add to the effectiveness of the 

 beak as a weapon or tool, owing to its extreme light- 

 ness, R. vigil of course being an exception. 1 



The Cuckoos are represented in Borneo by a number 

 of species, all but two of which are parasitic, laying 

 their eggs in the nests of other birds. The two species 

 which make their own nests are Carpococcyx radiatus 

 and Centropus sinensis. Nothing much appears to be 

 known of the habits 2 or nest of the former species, 



1 Dr. Hose kindly sends me the following note : " The casque 

 of Buceros rhinoceros is hollow except for a fine network inside, and 

 it has occurred to me that it might possibly affect in some way the 

 call of the bird, which makes a deep note resounding through the 

 jungle. Hornbills make holes in trees sometimes, and the heavy 

 bill with a casque attached would, it seems to me, be of some use 

 in so doing." E. B. P. 



3 Dr. Hose informs me that Carpococcyx, like Centropus, frequents 



