CHAPTEK XVIII. 



THE DISTRIBUTION OF THE FAMILIES AND GENEKA OF BIRDS. 



Order I.—PASSERES. 



Family 1.— TUEDID^. (21 Genera, 205 Species.) 



The extensive and familiar group of Thrushes ranges over 

 every region and sub-region, except New Zealand. It abounds 

 most in the North Temperate regions, and has its least develop- 

 ment in the Australian region. Thrushes are among the most 

 perfectly organized of birds, and it is to this cause, perhaps, as 

 well as to their omnivorous diet, that they have been enabled to 

 establish themselves on a number of remote islands. Peculiar 

 species of true thrush are found in Norfolk Island, and in the 

 small Lord Howes' Island nearer Australia ; the Island of St. 

 Thomas in the Gulf of Guinea has a peculiar species ; while the 

 Mid- Atlantic island Tristan d'Acunha, — one of the most remote 

 and isolated spots on the globe, — has a peculiarly modified form 

 of thrush. Several of the smaller "West Indian Islands have 

 also peculiar species or genera of thrushes. 



The family is of somewhat uncertain extent, blending insensibly 

 with the warblers (Sylviidae) as well as with the Indian bulbuls 



