AVES 



231 



The birds are grouped into about twenty orders, of 

 which only the eight most important ones will be dis- 

 cussed. 



Passeres : Perching Birds 



This order includes approximately one half of our species. 

 They may be recognized by the presence of four un webbed 

 toes all on the same level and with joints in number 2, 3, 

 4, 5, respectively from the first (inner) toe to the fourth 

 (hind). All our song birds belong to this group, of which 

 the families here given have representatives in most local- 

 ities. 



Flycatchers (Tyrannidae) . The members of this family 



FIG. 265. Phoebe with its mud nest in the corner of an old boathouse. Photo- 

 graphed in the Academy of Natural Sciences, Philadelphia. One third natural 

 size. 



are so named because they feed largely on aerial insects 

 which they seize in flight. Hornaday says every flycatcher 



