78 ELEMENTS OF ORNITHOLOGY. 
do Puff-birds. They give out either a mellow, musical note or a 
whistling sound. 
Beaks still larger, and occasionally much heavier than those 
of any of the lately mentioned groups, are found in the 
Hornbills. These Birds are much larger than Toucans, 
Fig. 80. 

The Red-necked Hornbill (Buceros ruficollis), 
and they are as entirely confined to the warm parts of the 
Old World, as the latter are to those of the New. MHornbills 
are found in Ethiopic Africa and the warmer parts of Asia, 
down to New Guinea, where the Red-necked Hornbill (Buceros 
ruficollis) is to be met with. These Birds have a very curious 
habit. The Hen makes her nest within a hollow tree, and there 
