PASSERES. BUCEROTID^:. 



loud discordant noise. They perforate the trunks 

 of trees from the side, making a hollow in the 

 wood, in which the nest is formed ; and the female 

 usually lays four eggs." The noise alluded to in 

 the above description, produced by the flapping 

 of their heavy wings in flight, combined with that 

 occasioned by the clattering of their mandibles, is 

 said to be so great as to inspire terror, when the 

 cause is unknown ; and to resemble those flaws of 

 rough and sudden winds, which often rise so un- 

 expectedly in tropical regions, and blow so vio- 

 lently. The larger species are extremely shy, and 

 difficult of approach : like some of the Corvidce, 

 they usually perch on the leafless branches of the 

 loftiest trees, when their vision, unimpeded by 

 foliage, ranges over a wide extent. 



The singular excrescences which in most of the 

 species arise from the beak, sometimes equalling 

 that organ, large as it is, in size, not only in dif- 

 ferent species vary much in form and size, but 

 even in the same species at different stages of its 

 life ; indeed, in very young birds there is no trace 

 of its existence.* The perpendicular furrows which 

 are seen on the sides of the upper mandible, are 

 supposed by the Europeans resident in the Mo- 

 luccas to be dependent on age, one being ac- 

 quired every season ; and hence they give the 

 Hornbills the appellation of Jerar-vogel, or Year- 

 birds. We have remarked on its lightness, owing 

 to its cellular structure, permeated by air ; but it 

 is also observable that the bones of the body and 

 limbs are more completely penetrated by this 



* The knife-like ridge on the summit of the beak in Crotophaga 

 ani, is in like manner totally wanting in the young bird ; as we have 

 found by personal observation. 



