214 BIRD BEHAVIOUR 



Duck, lives and breeds well there, the most spe- 

 cialized of all its breeds, the Penguin Duck 

 apparently the ancestor of the so-calleld " Indian " 

 Runner, so deservedly popular nowadays being 

 characteristic of the Malay Islands, so that, though 

 even in this country young Ducklings are found to 

 be very intolerant of heat, it must have been long 

 and perfectly acclimatized in the East ; and many 

 of the migratory Ducks I watched in confinement 

 in Calcutta showed distinct signs of wishing to 

 breed. 



On the whole, then, there is little evidence 

 that the direct effect of heat itself has influenced 

 the spring-time ebb of bird-life away from the 

 tropics ; but its indirect effects, as hinted above, 

 are another matter, and apropos of this it may be 

 noted that in the Bombay famine of a few years 

 ago the game-birds, which could not migrate, 

 suffered and died just as if they were mammals, 

 while better flyers escaped. 



Then there has to be taken into consideration 

 the attitude of the bird-population of the tropics 

 themselves. It is true that this is so numerous 

 and varied that the huge tidal wave of migrants 

 from the north into India makes no more obvious 

 difference to the human observer of the bird 

 population than does the influx of the football 

 crowd into London on the occasion of the great 

 Cup-tie contest to the apparent fulness of the 

 metropolis, and no doubt things are much the 

 same elsewhere. 



