INTRODUCTION. xxiii 



for instance, seeking flooded districts, others migrating 

 to avoid a damp climate. 



Mere temperature — heat or cold — seems to affect 

 birds but little, provided there is not excessive damp 

 and that the food is abundant. This is shown by the 

 ease with which tropical birds can be kept in the open 

 in temperate countries, while, conversely, birds from 

 temperate regions will often live well in the tropics, 

 though there are exceptions in both cases. 



The range in some species of birds is very wide, 

 especially among birds of prey and aquatic species. 

 Our Barn Owl, Peregrine Falcon, and Cormorant, for 

 instance, are found nearly all over the globe, and the 

 Turnstone, except in the breeding season, practically 

 ever3rwhere. 



A most remarkable distribution is that of the Fulvous 

 Tree-duck {Dendrocycna fulva), a member of a tropical, 

 non-migratory group of water-fowl, which is, notwith- 

 standing, found in Africa, India and tropical America. 

 Several families of non-migratory birds, it may be men- 

 tioned, have this distribution, that is to say, all round 

 the world in hot climates. Some tropical families also 

 may be noted to send forth outlying forms into temperate 

 regions ; such are the Cuckoos, Parrots, and King- 

 fishers, of which a few species may be found in temperate 

 climates, though most are tropical. 



The bird with the most limited numbers of any 

 is probably the Narcondam Hornbill (Rhytidoceros 

 narcondami), which is confined to the Island of Nar- 

 condam, a small wooded hill rising out of the Bay of 

 Bengal, only about three square miles in area, and 

 estimated to hold two hundred of these birds. Birds 

 with a limited habitat like this are, of course, particularly 

 liable to extermination if any change in condition occurs. 

 Ground -living species in such places have often lost the 

 power of flight, and hence soon fall victims to such 

 animals as cats, rats, and pigs, which accompany man. 



