THE RUFFED GROUSE. 155 
keeps it up until he becomes weary. This booming, 
which is not unlike, the roll of a kettle-drum, is very de- 
ceiving, for it sometimes seems afar off, and at other 
times quite near. This peculiarity has led some persons 
to imagine that he possessed ventriloquial power, but 
this is evidently a mistake, as he does not use his voice 
during the exercise. Many sportsmen think the drum- 
ming 1s produced by striking the wings against the log, 
which is often hollow, and a few naturalists suppose that 
it is caused by the violent contact of the wings with each 
other, or with the sides, but neither of these theories 
seems satisfactory, as the same sound is produced on a 
stone or amid heavy shrubbery. The wings being par- 
tially concave on the inner side when they are in motion, 
it is plausible to suppose that their extremely rapid vi- 
bration through the atmosphere, and the consequent 
compression, expansion, and escape of the air under 
them, would cause the drumming or booming which is 
the cause of so much speculation among sportsmen and 
naturalists. It certainly does not seem plausible to sup- 
pose that such a sound could be produced by beating the 
pinions together, against the sides, or against a log, for 
it cannot be heard any distance away until the wings 
commence vibrating very rapidly, and it increases in 
volume and intensity in proportion to the velocity of 
their movement. The drumming commences between 
February and April, according to the mildness of the 
climate in the country where the birds have their habi- 
tat, and is continued until all the fertile birds have 
paired. Barren hens often drum during the summer, 
and the young males in autumn, as soon as they separate 
from the mother. 
The booming is heard more frequently in the morning 
and evening than at any other time, during the calling 
season, but it is persistent in cloudy days, and is often 
continued all night. Some farmers and hunters say that 
