HANDIGAPPING HELMETS 51 



food thrown to them in the aviaries in zoological 

 gardens. 



Even the biggest and most specialized Hornbills 

 and Toucans like animal food, tiiough the '• horn " 

 of the former must often baulk them in obtaining 

 prey from crevices and holes ; for I once had a 

 narrovvr escape from a nasty dig in the face from- a 

 Concave-casqued Hornbill {Dichoceros bicomis) con- 

 fined in a hutch' in the Calcutta Bird Market; 

 about half the bill passed between the wooden bars, 

 but the broad helmet acted as an efficient " stop " 

 and spoilt the stroke. Buffon was often fanciJEul. 

 in his remarks on animal structure, but I fancy he 

 was right when he referred to the " horns " of the 

 Hornbills as an actual hindrance in food-getting. 

 It would be interesting to know whether the great 

 helmet only developed after the birds had become 

 more definitely fruit- eaters, or whether the in*- 

 convenience of possessing it tended to develop their 

 diet in that direction* 



There is probably, however, some connection 

 between the adoption of a vegetable diet and large 

 size, for nearly all the biggest birds are either 

 vegetable- or carrion^feeders, i.e. eat food which 

 does not require mobilitj' to obtain it, and can be 

 obtained in bulk if at all, so that, if the digestion 

 permits its assimilation, size is favoured and tends 

 to increase. 



Reverting to the Woodpecker-Barbet-Toucan 

 alliance, it is interesting to note that the Wood- 

 peckers in spite of their specialization for grub- 



