298 INSESSORES. 



SECTION II. 



ORDER II. INSESSORES, OR PASSERES. PERCHING 

 .. .: BIRDS. 



These birds are of smaller size than those of the other orders. 

 Naturalists regard them as exhibiting, in the highest degree, those 

 properties by which, as a class, birds are distinguished. 



So many are the variations of form and structure which are 

 found in this group, (about equaling in number that of all the 

 other orders taken together,) that but few positive characters" can 

 be assigned, which are common alike to the whole group and to a 

 particular division. Its distinctions are mostly negative ; for the 

 group includes neither swimmers, waders, nor climbers, neither 

 rapacious nor gallinaceous birds ; and yet, by comparing the va- 

 rious tribes which it includes, a general resemblance of struc- 

 ture becomes apparent. 



These birds have the power of grasping the branches and twigs of 

 trees with their feet, and are accustomed to rest upon them ; hence 

 they are called Perchers ; (Plate X. fig. 4.) the hind toe is al- 

 ways present and placed on the same level or plane as those in front ; 

 and the claws are incapable of being raised as in the Birds of 

 Prey. The larger portion of the species usually dwell in woods 

 and thickets. All have the faculty of flight in full perfection, 

 and in the Swifts and Humming Birds it may be regarded as at 

 its highest development. The beak in the Perchers differs 

 greatly in form, but its common shape is that of a cone, more or 

 less lengthened. In some of the genera a notch appears near 

 the tip of the upper mandible, indicating some affinity for the 

 habits of the Falcon tribe ; but. this gradually disappears in the 

 others. 



The food of these birds is various in its kinds ; but by far the 

 larger part feed either upon insects or the seeds of vegeta- 

 bles, which they almost always procure by the beak alone. 



This order has peculiar interest as including the sweet song- 

 sters whose soothing influence is so widely felt and acknowledged. 



The larynx, or organ of voice, is in these birds always of 

 complex structure, so that there are few of them that do not, du- 

 ring the pairing season, either sing or utter some peculiar note or 

 chatter analogous to song. 



The instinct of birds in building their nests, is in those of this 

 order most strikingly displayed. Admirable indeed are the com- 

 pact felted nests of the Humming-bird, of the GolHfmoli or Voi 



