176 SCANSORES. 



ORDER III. SCANSORES. 



(Climbing Birds.) 



THE association of the Families usually arranged 

 in one group, under the above title, or that of 

 Zygodactyli, or yoke-footed birds, is by most na- 

 turalists felt to be unsatisfactory. Unlike in food, 

 in form, in habits, and economy, the single charac- 

 ter which they have in common, is that their four 

 toes are arranged in two pairs, the outer toe being 

 turned backward more or less permanently, like 

 the thumb, so that these are opposible to the 

 middle and inner toes, which point in the opposite 

 direction. From this structure results a more 

 efficient power of grasping, or of clinging to per- 

 pendicular or reversed surfaces, associated with 

 climbing habits in the principal Families, as those 

 of the Parrots and the Woodpeckers. 



In the other Families, however, those of the 

 Toucans and the Cuckoos, this disposition of the 

 toes is not accompanied with the power of climb- 

 ing, properly so called ; though the latter, and 

 perhaps the former, do certainly move about the 

 branches of trees, in a manner diverse from that 

 employed by the true perching or Passerine birds. 

 At the same time it must be borne in mind that 

 the faculty of climbing, even if common to the 

 whole of this Order, is by no means peculiar to it ; 

 as the Creepers and Nuthatches, whose toes are 

 arranged on the Passerine type, can climb and 



