500 ARTIFICIAL PROPAGATION OF GROUSE 



response to proper management is one of the most important items controlling production. Nor 

 are these as yet clearly defined, for each improvement in rearing technique, as developed, 

 increases the ability to raise more and more birds. Also such items as their comparatively 

 limited egg production and their intolerance of each other, during certain periods of the year, 

 due to the dominance complex, invoke unusual restrictions on the grouse breeder seldom 

 encountered in raising pheasants or quail. 



On the degree to which man can learn how to stimulate the full reproductive capacity of 

 grouse in captivity rests, in no small measure, the ultimate chances of success. Among the 

 stimulating techniques adopted to date, some ha\e proven satisfactory answers to the prob- 

 lems they were intended to solve, with others considerable progress remains to be made. In 

 this latter group lie three objectives which must be realized before ultimate success can be 

 attained. They are: 



1. An increase in the number of eggs produced per female during the breeding season. 



2. An increase in egg fertility and hatchability, particularly during the latter portion of the 

 laying period. 



3. A much higher average survival rate among chicks from five to 25 days old. 

 Indications are that the first of these problems may eventually be solved by selectively 



breeding for high egg production, which is apparently an inherited characteristic. A total of 

 170 ova have been recognized in a single female at the start of the breeding season. On the 

 other hand, though an individual bird at the Research Center has laid 36 eggs in a single 

 year, the normal is but 15 to 20. Another key to this situation might be food. Examining 

 this possibility, however, we find the grouse in captivity, irrespective of the number of eggs 

 laid, lose very nearly the same weight during the breeding season as do their wild cousins. 

 Likewise, the threshhold of reproductive exhaustion seems to lie between 500 and 515 grams 

 for both groups. It is a fact that high producers eat more although losing about the same 

 weight as low producers. The average weight at the beginning of the breeding season of the 

 ten grouse laying the most eggs at the Center in 1942 was 556 grams in comparison with 552 

 grams for the ten poorest producers. The average weight of the respective groups shortly 

 after the last egg was laid was 513 and 515 grams. Though exact records of food consump- 

 tion during the interval were not kept, the attendant conservatively estimated that one-third 

 more food was eaten by the higher producing group. 



The problem, then, may be one of building up a strain of birds which produce more eggs 

 because they are physiologically capable of maintaining production weights on game farm 

 diets throughout most of the breeding season. Further progress in adapting these foods to the 

 nutritive requirements of the bird probablv is dcpendenl upon fundamental advances in the 

 field of bird nutrition. 



The second problem, that of securing fertile eggs , is largely traceable to the peculiar 

 psychological behavior of the grouse during the mating period. This has already been 

 described*. 



The difficulties here are several. In the close confinement of a pen the male may so frighten 

 the female by his pugnacious, dominating tactics that mating may not occur. Due to this 

 harrassment, her weight may decline abnormally, thus lowering egg yield. A second limita- 

 tion involves those males in which the reproduitive cycle appears to be of such short duration 

 that the period during which the female will accept the male does not fall within it. If the 

 male is vigorous, one service is usually good for a clutch of eggs. However, the female that 



* See Chapter II, p. 65. 



