ORDER PASSERIFORMES 



species of birds. It is regarded as the order 

 in which evolution has reached the most 

 advanced stage that birds have attained, 

 both in respect to physical structure and 

 mental development. While many of its 

 distinguishing characters are anatomical, there 

 are some external ones. The feet always 

 have four toes, the first toe being always well 

 developed, directed backward and provided 

 with a long claw, and inserted at the same 

 level as the others,, thus making a foot es- 

 pecially adapted to perching on small branches 

 of trees. None of the other toes can be moved 

 to point laterally or backward. The wings also 

 have certain characters, the primary quills 

 (the largest, and anterior or outer ones) al- 

 ways numbering nine or ten, the secondary 

 quills always more than six (usually nine), 

 and the wing coverts are always compara- 

 tively short, leaving at least half of the 

 length of the secondaries exposed. The 

 perching birds are mostly of small or very 

 moderate size, the crows and ravens being 

 the largest. The order comprises besides 

 several small Old World groups, two great 

 divisions or suborders, Tyranni and O seines. 



Suborder TYRANNI 



This group (called Clamatores in many 

 books) though of large extent, especially in 

 tropical and South America, has never re- 

 ceived any satisfactory and commonly ac- 

 cepted English name. It includes those 

 perching birds which have the vocal organs 

 with a less efficiently organized muscular 

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