THE NUTHATCH. 171 



pecker, and other birds of superior size, who build in the same 

 situation. No persecution will force this little bird from its ha- 

 bitation when sitting ; it defends its nest to the last extremity, 

 strikes the invader with its bill and wings, and makes a hissing 

 noise ; and, after every effort of defence, will suffer itself to bo 

 taken in the hand rather than quit." 



The above cut will serve to show the difference in structure 

 between the foot of the Woodpecker and that of the Nuthatch ; 

 the former, it will be seen, is zygodactilic, or yoked, two of the 

 toes being turned back, and two forward, and the two front ones 

 being joined together at their bases : thus the foot has two bear- 

 ings in the front and two behind, and the bird is enabled to perch 

 or to walk lengthways on a branch ; and with the feet alternately 

 holding on, and the tail acting as a prop, to walk up the trunk of 

 a tree, or even to move sideways round it. The foot of the Nut- 

 hatch is what is called anisodactilic, or unequally yoked : at a 

 first glance it seems not to differ much from a common foot, with 

 three toes before, and one behind ; but it is in reality a more 

 curious piece of mechanism, having the power of two feet, and 

 those combined. The middle and exterior toes are united toge- 

 ther at their bases, and admit of a position half reversed, or mid- 

 way between the other two ; the hinder toe is long and strong, 

 and all four of them have strong claws. Thus the foot can adapt 

 itself to any kind of surface, and the bird possessing it can run 

 upon the trunk or branch of a tree in any direction upward, 

 downward, across, or obliquely. 



V. PASSEEINE BIKDS.* 



THESE birds have a pointed, conical beak, generally strong, and 

 with both mandibles moveable, to fit it for the peeling of 

 grain. The feet, as in the singing birds, are slender and 

 divided. Some eat insects as well as seeds. Those which eat 

 * Passeres. Sperli'M/sartige Vogel, BECH. 



