CHAPTER VIII 



REPRODUCTIVE CAPACITY OF THE SPECIES 



By Frank C. Edminster and Walter F. Chissey 



REPRODUCTIVE POTENTIAL 



EFFECT OF SEX RATIO 



PROPORTION OF NON-BREEDING BIRDS 

 Males — Females 



EFFECT OF AGE ON BREEDING 



Longevity and Senility 



NUMBER OF EGGS LAID 



Yearly Variations — Variation in Difierent Regions of New York 



RENESTING 



Number of Eggs in Renests 



FERTILITY OF THE EGGS 

 VIABILITY OF THE EGGS 

 INBREEDING 



^ 



SUMMARY 



Normally, nearly all female grouse breed each s|)rin2. In some years, evidence shows that 

 up to 25 per cent of them may fail to breed in limited localities. Non-breeding by males 

 is unimportant, (p. 359). 



Both sexes breed the first year when they are about ten months old. (p. 359). 



An occasional wild grouse will breed when five years old or more. In captivity many breed 

 at this age and a few have reached six years and bred. (p. 359). 



No indication of the reproductive capacity of grouse being affected adversely by variations in 

 sex ratio was observed. Among newly-hatched chicks the proportion of males to females 

 is normally about equal but as summer wanes males tend to predominate among birds 

 of the year (p. 355). 



