154 VERTEBRATA: AVES OR BIRDS. 



The Passeres are the most active of all birds ; .and they 

 are regarded as the typical representatives of the Class, 

 being the most complex of all in the details of their or- 

 ganization. 



The Passeres include the OSCINES, or Singing Birds, as 

 the Thrushes, Blue-birds, Chickadees, Nuthatches, Creep- 

 ers, Wrens, Warblers, Tanagers, Swallows, Waxwings, 

 Vireos, Shrikes, Finches, Larks, Blackbirds, Starlings, 

 Jays, Crows, and their numerous allies, all of which have 

 a complex vocal apparatus, consisting of live pairs of 

 muscles, although many of them do not really sing ; and 

 the CLAMATORES, as the Flycatchers, whose vocal organs 

 are more simple or even rudimentary. 



The Thrushes or Turdidge have the bill notched near 

 the tip, the wings with ten primaries, the tarsi booted, 

 as in the robin, etc., or scutellate, as in the Cat-bird, etc., 

 and the feet very deeply cleft. The Wood Thrush, the 

 Hermit Thrush, the Robin, the Blue-bird, the Mocking- 



PIG. 160. 



Mocking-bird, Mimus pnbjglottus, Boie. 



bird, the Cat-bird, and the Brown Thrush are among our 

 most interesting species. It should be added, however, 

 that some writers class the Bluebirds under another fam- 

 ily the Saxicolidse. 



