850 ZYGODACTYLI. 



flight corresponds. It is unequal and jerking 1 , per- 

 formed with much flutter of the wings, as if the down 

 stroke of these were not very effective, which might 

 be inferred from the rounding away of the anterior 

 part of the keel and the feebleness of the furcal 

 bone. But they can raise the wing with great quick- 

 ness ; and, though their flight is far from being so 

 graceful as their form, they make way with con- 

 siderable speed. They are birds of the margins of 

 the waters, and especially resort to rivers which are 

 subject to flooding ; but they also sometimes hunt 

 for beetles by running along the bark of decayed 

 trees, and often choose the holes of these for nestling 

 places. 



STERNA OF THE ZYGODACTVLI. 



Of the birds which form this division we shall give 

 as specimens, the sternal apparatus of the common 

 green woodpecker, as being chiefly a bank bird, and 

 resembling in some of its habits the anisodactylic 

 birds, and of the common jacko, or grey parrot, which 

 is one of the most scandent. The cut on next page, 

 that of the woodpecker, is of the natural size. 



This is a very peculiar sternum ; and upon looking 

 back to what is said of the foot, or, far better, by 

 watching the habits of the bird itself, it will be found 

 to be one of very peculiar action. The bird, while 

 it seeks its food in the holes of trees, or excavates 

 them in making a resting hole for its young, rests 

 chiefly with the sternum pressed against the tree ; 

 and it will be seen, upon examining the profile, that 

 the bones are fully as much suited for answering 

 this purpose as they are for flight, though the great 

 length of the sternum, and the production of the keel 

 for the whole of that length, though not very high at 



