BRANCH CHORD AT A ; CLASS Al/ES : THE BIRDS 357 



several other species occur. In all seventeen species 

 have been found in the 

 United States. The nests 

 (fig. 140) of the hummers 

 are very dainty little cups 

 lined with hair or wool or 

 plant -down. The ruby- 

 throat lays two tiny pure- 

 white eggs. 



The perchers (Passeres). 

 Nearly one-half of the 

 birds of North America be- 

 long to the great order Pas- 

 seres, and of all the known 

 birds of the world more than 

 half are included in it. The 

 Passeres or perching birds 

 include the familiar songf- 



O 



birds and a great majority 

 of the birds of the garden, 

 the forest, the roadside, and 

 the field. The feet of these 

 birds always have four toes 

 and are fitted for perching. 

 The syrinx or musical ap- 

 paratus is, in most, well 

 developed. The nesting 

 and other domestic habits 

 are various, but the young 

 are always hatched in a 

 helpless condition and have FIG. 140. Nest and eggs of ruby- 

 to be fed and otherwise throat . humming bird, Trochiius 



colubrts, seen from above, in apple- 

 Cared for by the parents for tree. (Photograph by E. G. Tabor; 



a longer or shorter time. Permission trflfocmillan Co.) 

 The North American species of this order are grouped into 



