So BIRD BEHAVIOUR 



between the small Magpie-sized Hornbills of the 

 genus Tockus, with little or no " top-story " to the 

 bill, to the large typical Hornbills, often as big as 

 hen Turkeys, with enormous bills generally crowned 

 with a great horny excrescence. The smaller kinds 

 are more insectivorous than the larger, and thus 

 show some approach to the Wood-Hoopoes (Irrisor), 

 which have much more curved bills than the ordinary 

 Hoopoes, and feed when on trees, while the common 

 Hoopoes are ground-feeders. 



It has been well suggested that the great bills of 

 the larger Hornbills and Toucans are adapted to 

 giving a purchase for wrenching off tough-stalked 

 fruit ; as the birds grew bigger, too, they would 

 not be able to venture on such slender branches, 

 and so would need more to reach out for their food. 

 And if the beak had got merely longer without 

 acquiring bulk, any wrenching effort would have 

 been liable to dislocate it. That Hornbills at any 

 rate work their beaks very hard may be inferred 

 from the facts that in the largest and bulkiest-beaked 

 kinds the edges of the jaws are worn and chipped 

 in elderly specimens, and that if the fruit will 

 not come away by fair means, some Hornbills think 

 nothing of throwing themselves bodily off the 

 bough and wrenching it away by sheer weight. No 

 doubt the effort of recovering their perch in 

 gymnastic exercises like this is what gives these 

 particularly awkward-looking birds the deftness on 

 the wing which many people must have observed 

 when watching them catch in the air grapes or other 



