288 The Ruffed Grouse 



eggs than any other size. The yearly average varied from ten and 

 nine-tenths per nest to eleven and nine-tenths, with no regular 

 trends. There is probably no significance in these moderate varia- 

 tions. 



It is likely that most egg complements below seven are the result 

 of physiological deficiencies in the female, and those exceeding six- 

 teen are probably the product of two separate females. A nest that 

 contained nineteen eggs was definitely known to result from two 

 birds, as was also one sixteen-egg nest. 



The size of the clutch in renestings following the destruction of 

 the first nest is much smaller than in the first attempt. The earlier 

 in the season a nest is destroyed, the larger is likely to be any second 

 nest chitch that is laid. In sixty second nests throughout New York 

 the number of eggs ranged from three to twelve and averaged seven 

 and nine-tenths. One case observed was apparently a third attempt 

 at nesting, as judged by the time the eggs hatched (about July 

 25) (data taken from N. Y. S. Cons. Dept Ann. Reports). 



Fertility of the Eggs; Hatchability. The fertihty records of several 

 hundred first nests were obtained in New York State from 1931 to 

 1941. The average proportion of infertile eggs was about two per 

 cent, the maximum in a single year three and five-tenths per cent 

 and the lowest one and one-tenth per cent. There was no regularity 

 in the variations and apparently no significance in them. The de- 

 gree of infertility did not reach a high enough level any year to 

 indicate any serious trouble. Records were obtained for a number 

 of renests too. These averaged a little higher in the proportion of 

 infertile eggs (for example, 5.4 per cent in 1937), thus confirming 

 the well-established fact that fertihty is lower with late breeding. 

 This factor is of little significance, however. 



These records may indicate higher rates of infertility than ac- 

 tually took place. Any egg not hatching that showed no embryonic 

 development was considered to be infertile. A fertilized egg that 

 dies within a few days of the start of incubation will present the 

 same appearance; hence any cases of this nature that may have oc- 

 curred were placed in the wrong category. This only further em- 

 phasizes the consistently low infertility rate. 



When we consider the rather complex nature of the breeding of 

 grouse, the near-perfect results are remarkable. Certainly we do not 



