ANNIAI, I'KUSISTKNCV A XI) KCG l'l{()!)l'( TION 



197 



A slifi'nt luit siiiiiilKMiit <'i»rrfl.ili(ni is fdiind lo fxist luMweeti winter rate of 

 layiiiir and persisteiu\ . This correlation indicates lliat, in jjeneral, there is 

 some tendency for tlie more intense winter layers to jiersi.st in layiii'; later in 

 the fall than do les> intense layers. 



,s. ('(irrel'ilii>ii lutxceeii ]\'iiiltr Rate (/ri'dtii llniii the Mtaii (iiitl Hii/li 

 f^ersLtfenci/. 



Ry classifying all liirils with higher winter rates than the mean of the 

 whole |)oi)idation as hiuh for rate, and by classinju' as highly persistent all in- 

 dixiduals laying for ;JI5 days or more, the following table gives the correla- 

 tion between high winter rate and the presence of ]iossible genetically high 

 persistency: 



Coeflicient of ciirrelation +.2236±.0138 



The above tabulation presents a moderate degree of positive correlation 

 between two inherited characteristics concerned in high fecimdity. The very 

 significant fact is brought to light that high winter rate and high persistency 

 are ]iartially conn)lementary, and there is no evidence of antagonism between 

 t1ie two. 



f). Corrc'iillnii Bi'xiueii LeiKjth of Winter Pause (iti'l JiDinal Pemintenci/. 



The j)resence or absence of winter ]iause has been shown by Hays (1921) 

 to dej)cnd u])oii genetic factors. '1 he duration of the pause, however, may 

 depend upon en\ironment as well as inheritance. Most environmental forces 

 alTecting the duration of pause are ])roi)ai)ly beyond control of the breeder 

 ;;nd may not properly be considered in this rei)ort. This section is devoted 

 to a study of the correlation between length of pause and persistency as has 

 already been done by Hays and Sanborn (I{)26b). In the ])()pulation being 

 studied there were 131S birds with winter pause records which were divided 

 into ten-day class inters als and the following constants arrived at: 



Number of birds 1348 



Mean length of winter pause 32.39 



Pause standard deviation ..... ±21.77 



Mean annual persistency 309.03 



Persistency standard deviation .... ±54.89 



Coefticient of correlation -f .1017±.0182 



Regression persistency on pause .... -|— 256 



Regression pause on persistency .... -(—040 



