234 w - v - I-AMHKRT AND C. W. KNOX. 



different dates and the rate was determined by dividing the total 

 number of eggs laid 1>\ the number of days between the date of 

 first egg and the beginning of the hatching season. The correla- 

 tion coefficient in this case was - - 0.048 o.i 1 1 . This correla- 

 tion likewise is not significant and indicates, in this particular 

 group of birds, that preceding production has not influenced the 

 sex ratio. 



In a study of the sex ratio based on hatches throughout the 

 entire year Jull (1924) found a correlation of - 0.704 0.031 

 between the sex ratio and antecedent egg production. As the 

 season advances the ratio of males decreases, and Jull concludes 

 that the cause for this decrease is directly related to the ante- 

 cedent egg production. 



The rate of egg production during the hatching season, like- 

 wise, was found not to have influenced the sex ratio in this 

 group of birds. The correlation coefficient between total pro- 

 duction during the hatching season and the sex ratio was 

 - 0.009 0.108. This correlation, like the two preceding, is 

 not significant being much smaller than its probable error. 



Since the correlation coefficients in all three cases were negative 

 and smaller than their respective probable errors the conclusion 

 is justified that neither mean egg weight, as measured for each 

 bird nor the rate of production both preceding and during the 

 hatching season has influenced the sex ratio. In other words 

 there is no tendency for those birds laying the fastest or laying 

 the heaviest eggs to produce more or less males than the birds 

 producing the fewest or the lightest eggs. 



The correlations between these three variables together with 

 their respective ranges, means, coefficients of variability, and 

 standard deviations are shown in Table V. 



DISCUSSION. 



The data presented herein for the most part show a higher 

 sex ratio than has been reported by other investigators. Mussehl 

 (1924) reporting a sex ratio of 52.24 per cent, is the only one 

 reporting a higher percentage of males. Cole and Kirkpatrick 

 (1915) report approximately the same sex ratio in pigeons as is 

 reported by the present writers, namely 51.06 per cent. All 



