474 
Bulletin No. 162. — 1915. 
A review of the proportion of males to females in the different 
age periods displays surprisingly little fluctuation, it never being 
greater than 107.9 nor less than 105. Certainly these differences are 
not great enough to account for the prevailing impression of the 
higher mortality of females in the earlier stages, and do not furnish 
any substantiation of such a notion. 
There still remains the possibility of a difference in the death rate 
of the two sexes after reaching what we have called adult life, and this 
will be examined next. This group, it will be recalled, includes 749 
birds which attained the age of six months or more. Of these 125 
died from “natural” causes, 391 were alive on December 1, 1914, and 
233 were killed, sold, or otherwise disposed cf at periods presumably 
shorter than would have been their natural space of life. Table II 
summarizes the data for the first two classes — those which died 
natural deaths and those which were alive at the time of compilation. 
These two classes together represent a total of 516 birds, the females 
being considerably in excess. The numbers are, 244 males and 272 
females. For purposes of tabulation they have been divided into 
periods of 1 year, except the first group, which is only a six-month 
period, including birds between six months and one year of age. 
