TJBNCIROSTRES. 121 



Many of them are bark birds, which run in all direc- 

 tions upon the boles and larger branches of trees, 



Nuthatch. 



and extract the insects or larvae which are lodged in 

 the crevices. Some of them run upon walls and 

 rocks, and catch spiders in the same manner ; while 

 some again hover over the nectaries of flowers, from 

 which they extract honey or small insects. They 

 are an interesting race, from the agility of their 

 motions, often for the brilliancy of their colours, fre- 

 quently for their great power of wing as compared 

 with their size, and not unfrequently for their extreme 

 littleness. The humming-birds, which make the air 

 under the action of the equatorial sun so gay with 

 gleamy tints as if all the gems and the finest metals 

 were flying about, belong to this division ; and some 

 of them, while to appearance not bigger than humble- 

 bees, have the sternum and all the apparatus of flight 

 nearly as well developed and as perfect as in the jer- 

 falcon. 



But though this division is a very natural one, it is 

 doubtful whether the bill is the best foundation for 

 their natural distinction from other birds, as it is nei- 

 ther their most constant nor their most conspicuous 

 character. The bill is always slender at the tip, and 

 it cannot be said in any instance to be thick in pro- 

 portion to its length, but it is often a large bill for the 



