CHARACTERS OF PASSERES d 



•ditions of fusion of tlie envelope — those showing the entire lat- 

 ■eral plates, sharp^ridged behind, whether or not the front of 

 the tarsus be also fused — are commonly associated with certain 

 anatomical characters which affect the vocal powers of the 

 birds; there being a complex arrangement of the muscles of 

 the lower larynx. Most of the North American Passeres exhibit 

 these features combined, and constitute a minor group Oscines, 

 which is denominated a suborder by those who hold Passeres as 

 an order. The family of the Larks [Alaudidce) is the only 

 exception among our birds ; for here the larynx is a highly- 

 developed vocal organ, while the tarsus shows a different struc- 

 ture of the envelope, being covered on the outer side with two 

 series of scales lapping around before and behind, and having 

 the hinder edge blunt. This state of the tarsus prepares us for 

 the further modification witnessed in a single one of the North 

 American families of Passeres, namely, the Tyrannidm, or Fly- 

 catchers, in which the tarsus is blunt behind, being covered 

 with a set of variously-arranged plates lapping entirely around. 

 Such condition, in connection with an incomplete development 

 of the vocal organ, marks off the Tyrannidce as representatives 

 of a second minor group of Passeres, called Clamatores, in con- 

 trast with Oscines. 



The purpose of these opening paragraphs will have been at- 

 tained, if enough has been said to enable the reader to gain an 

 idea of the limits, and of certain leading features, of the great 

 group Passeres, which includes the majority of all "known birds, 

 and something like two-fifths of those of North America. 



The families of Passeres which occur in the Goloradan region 

 are the Turdidce, Saxicolidce, Ginclidm, Sylviidm, CJiamaidcB. 

 Paridce, SittidcB, Certhiidce, Troglodytidce, Alaudidce, Motacillidce. 

 Sylvicolidce, Tanagridce, Sirundinidce, Ampelidw, Vireonidce, Lani 

 idee, Fringillidce, Icteridce, and Corvidce, all of which are Oscine 

 and the Tyrannidce, which is Clamatorial. These will be sever' 

 ally considered in the sequence here indicated. 



With these few preliminary considerations touching the Pas- 

 seres at large, we will at once take up the subject of the present 

 chapter, namely, the 



