WINTER CYCLE AND WINTER TAl^SE 



181 



able error, it is of such small ina<;nitude .as tt> indicate praclical iiKicpciid- 

 cncc between the characteristics beinK considered. 



/<"i. Correlation Between Winter Clutch Size Beloic the Mean and the Pres- 

 ence of Winter Pause for Entire Population. 



Coefficient of correlation 



+.3412 ± .oias 



A significant positive correlation between small winter clutch and the pres- 

 ence of winter pause appears above. In general, there is a greater tendency 

 for birds that lay in small clutches to pause than for birds laying in larger 

 clutches. The rate of functioning of the reproductive system" must therefore 

 bear a relation to winter pause. 



19. Correlation Betzceen Annual Rale or Inlensity and Length of Winter 

 Pause. 



Annual rate represents or approximates the intensity of each individual 

 bird for the pullet laying year. Inasmuch as this constant has been discussed 

 in Technical Bulletin No. 7 of this station, space will not be occupied here 

 by further discussion. Since winter pause represents a period of non-pro- 

 duction, there must of necessity exist a negative correlation lietwcen annual 

 rate and length of winter pause unless pause birds lay at a higher net rate 

 than non-pau.se liirds. This la.'^t point is, in part, discussed in section 16 of 

 this report, where the net winter rate of the total population in relation to 

 the pause and non-pause groups is considered. The important positive rela- 

 tion between annual rate and annual egg record makes the correlation be- 

 tween annual rate and length of winter pause of importance. Included in 

 this study are the 1348 birds exhibiting winter pause and having complete 

 annual records. The following constants were determined: 



Number of birds 



Mean annual rate ...... 



Annual rate standard deviation . 

 Mean length of winter pause . . 

 Winter pause standard deviation 

 Coefficient of correlation .... 



Regression of annual rate on winter pause 

 Regression of winter pause on annual rate 



1348 



53.79 

 ±9.07 



32.29 

 = 21.77 



—.4091 ±: .0153 



—.170 



—.982 



