244 BOMBAY DUCKS 
Since the coppersmith’s note is not confined to the 
breeding season, it is presumably not a love song de- 
signed to attract the attention of the opposite sex. 
Further, every bird seems to be able to emit but one 
note, and, as it will pour this forth by the hour at times 
when apparently there is not another member of the 
species within earshot, the note cannot be conversa- 
tional. 
I believe that the song of most birds is simply an 
ebullition of surplus energy, an expression of perfect 
health, an outward and audible token of pure and un- 
alloyed happiness. I do not mean to say that birds 
cannot communicate vocally with one another, for they 
can and do, Their calls are, however, sharp, short notes, 
easily distinguishable from their songs. 
Just as a man, when he is in good health and spirits, 
will sing while having his bath, so do the little copper- 
smiths pour forth their notes. In the former case, the 
‘pleasing contact of the water braces the nerves and 
forms the immediate stimulus ; in the latter, it is sun- 
shine that sets the birds’ vocal cords in motion. 
Coppersmiths love not the cold; consequently they 
do not ascend the hills. In Northern India, during the 
cold weather, their voice is completely hushed ; but as 
soon as the warmer days come, the birds strike up; 
and, the hotter the weather, the more vociferous they 
grow. Thus the coppersmith bird might be called 
nature’s thermometer. It will not, as a rule, sing if 
the temperature falls below 70°, while the warmer the 
weather, the louder is its note. In Madras the ther- 
mometer is rarely in the sixties; hence all day and 
