132 THE STORY OF THE BIRDS 



regions, but absent from the western portions of 

 the Palaearctic Region, from the extreme northern 

 portions of the Nearctic Region, and the extreme 

 southern portions of the Neotropical Region. 

 Included in this sub-family are those Swifts, the 

 nests of which furnish the famous bird-nest soup 

 of the Celestial Empire. These birds form the 

 genus CoUocalia, and range from Madagascar 

 across the Eastern Tropics to New Guinea and 

 the Marquesas Islands. The third sub-family 

 contains the Tree Swifts (Macropteryginae), which 

 are distributed over various parts of the Oriental 

 Region, and in many of the Malay islands be- 

 longing to the Australian Region as far east as 

 the Solomon group. The Humming-Birds 

 (Trochilidae) are confined to the New World, 

 where, however, their range is an enormous one. 

 These feathered gems — the loveliest of all avine 

 forms — are certainly the most wonderful and 

 remarkable feature of the bird-life of the New 

 World ; birds with no very close surviving re- 

 lations, with absolutely no representatives or 

 analogues in any other parts of the world, they 

 stand alone and unique in the avine kingdom. 

 But few species penetrate to the more extreme 

 northern and southern limits of the group's area 

 of dispersal, and even these are migratory, and 



