86 BIRD BEHAVIOUR 



The power of cracking the harder seeds is very 

 highly developed in the typical Parrots ; as may 

 usually be seen at the Zoo, the great Hyacinthine 

 Macaw {Anodorhynchus hyacinthinus) can crack a 

 Brazil nut with no more effort thah a Canary 

 bestows on a grain of hemp-seed. This cracking 

 and rejection of the husks of seed, etc., is particu- 

 larly characteristic of Parrots, and of Finches 

 among the Passerines, and in doing this the tongue 

 undoubtedly comes into play to some extent, as 

 may also be seen when a Parrot chews up a piece 

 of food, as the larger species at any rate do, these 

 showing the nearest approach to mastication that 

 is found among birds. 



The seed-cracking habit, however, occurs also in 

 the thicker-billed Larks ; the Larks, by the way, 

 are a group particularly well exhibiting the grada- 

 tion of beaks — our Skylark has an ordinary bill 

 suitable for any purpose, picking up seed, shoots, 

 or insects. From this a gradation can be traced 

 to the long thin almost Hoopoe-like bill of the 

 great Desert Lark (Certhilauda alaudipes), only 

 suited for digging and probing for insects ; and on 

 the other side to the great heavy seed-cracking bill 

 of Clot-Bey's Lark (Rhamphocorys clot-bey), which 

 equals in size and strength that of most of the 

 " Grosbeaks " among the Finches. And as Larks 

 are only passerine birds, and very much alike except 

 for their beaks, the evolution here would seem to 

 be comparatively recent. 



Like the honey-sucking habit, the seed-cracking 



