ZOOLOGICAL SOCIETY BULLETIN 



The bill of the shell-ibis of India may be 

 likened to an ordinary lemon-squeezer, having 

 a cavity in which the half-lemon rests before 

 it is compressed. When the mandibles of this 

 bird are closely opposed the central portion of 

 the beak gapes slightly. In this cavity the bird 

 firmly holds the shells of the land-snails upon 

 which it feeds, until it can bring the pressure 

 of both mandibles to bear and so crush the 

 shell of the moUusk. 



The asymmetry of the bill, as seen in the 

 oyster-catcher, is not accidental, but constant, 

 in the crooked-billed plover of New Zealand. 

 In this bird the bill is permanently bent to the 

 right, a beautiful adaptation to help the bird in 

 its search for insects, which, in the dry country 

 that it inhabits, are found almost entirely 

 under stones. 



As a rule, beaks are rather immovable 

 throughout their length, but in the woodcock, 

 and to a less extent in the dowitcher snipe, the 

 extremity of the upper mandible can be raised 

 some distance, as the cut shows. This extreme 

 sensitiveness is especially necessary, as the 

 eves of the woodcock are placed very far back 

 on the top of its head, and are of little or no 

 use in seeking food. 



What an interesting study the various beaks 

 of land birds would oiifer, were we able to de- 

 vote to them the space which they deserve ! 

 They defy classification and refuse to be ar- 

 ranged in any linear sequence. The majority 

 of those birds which have their beaks armed 

 with a strong hook feed upon living prey — 

 from the great mandible of the golden eagle 

 to the tiny vireo, which snaps up the dancing 

 gnats. 



The owls and the parrots, which, by the way, 

 are much more closely related than most of 

 our classifications would indicate, have bills 

 very much alike, and afford a striking example 



of two large related groups of birds whose diet 

 has become radically unlike, although even in 

 this case "blood will tell" and the kea parrot 

 slips back into carnivorous habits with ease. 



Owls tear their prey apart with their beaks, 

 or swallow it entire, but parrots gnaw and 

 gnaw upon their nuts and seeds, reducing their 

 food to powder. This grinding and rasping is 

 aided by several file-like ridges which many 

 parrots have within their beaks. The hinging 

 of the upper mandible with the skull is more 

 evident in a parrot than in any other bird. 

 This arrangement allows much freedom of 

 motion. 



It vs not clearly known what use the immense 

 beaks of toucans may serve, although there 

 seems little excuse for this ignorance in those 

 who know the birds in their native haunts. The 

 delicate, spongy texture makes the clumsy- 

 looking appendages exceedingly light, and they 

 are usually banded or splashed with brilliant 

 hues — blue, yellow, red, brown, green or black. 

 But light as the beaks are in these birds, in the 

 unrelated but similarly monstrous-beaked 

 hornbills the weight must be considerable, for 

 the first two vertebrae of the neck in these lat- 

 ter birds are fused together, to yield a firmer 

 support for the muscles of the neck. 



Chimney swifts and hummingbirds both feed 

 upon insects and are rather closely related to 

 each other, but here again the most decided 

 difference is to be fourd in their bills. The 

 broad, flattened mandibles of the swifts open 

 wide, as the birds dash through the air, engulf- 

 ing gnats and flies with wonderful skill : while 

 the hummingbirds, as we all know, probe the 

 deepest calyxes. Could two bills more unlike 

 be imagined ? In very young hummingbirds 

 the bill is short and broad, very like the swift 

 type, but later its long and slender shape is 

 acquired rapidly : there are many resemblances 



