COMMON TO BOTH SEXES 267 



At the Research Center, it has been demonstrated that, under game farm conditions, one 

 male will readily mate with up to five females in a single pen*. But to just what extent the 

 reactions of such birds reflect conditions outside captivity, it is difficult to say. Stoddard^ 

 found that polygamy could be freely induced in captive quail but that monogamy was the 

 rule in the wild. 



Unfortunately, it has not been possible to observe these relationships directly among wild 

 grouse. Undoubtedly, however, cocks tend to mate with as many hens as visit their territories, 

 providing both birds are in the proper stage of the reproductive cycle. The usual evenness 

 of the sex ratio at this season and the fact that the birds are generally well scattered would 

 imply that this number is normally small. Similarly, it is unlikely that competition is often 

 sufiRcient to force a hen to associate with more than one male. In fact, the result may, in 

 many cases, amount to an enforced monogamy. On the other hand, there is considerable in- 

 dication that grouse are not averse to promiscuity if the occasion demands. 



It was long thought that male grouse are in constant readiness for mating throughout the 

 breeding season. Then, after considerable study, Allen" came to the conclusion that this 

 condition is not continuous, but that it is recurrent in what he termed "sex rhythm". Recent 

 experience with propagated birds at the Research Center, however, has shown that, while the 

 degree of readiness does fluctuate^, the right stimulus will induce mating even during low 

 periods in the rhythm. In general, males have been found to be able to breed successfully 

 over a period of three to four weeks. At the height of his cycle, one bird mated four times 

 in one day. Nevertheless, there is considerable individual variation. In fact, some birds ap- 

 parently never reach this stage during certain years. Its presence is indicated by the willing- 

 ness of a cock to attempt copulation with another bird which is in a posturing attitude, 

 although a lack of interest in one bird is no sign ihat another might not produce a positive 

 reaction. 



In the female, oestrus, the physiological condition which corresponds to heat in mam- 

 mals, has been observed at the Research Center to commence from three to seven days prior 

 to the laying of the first egg. The shorter period is more frequent. Its onset is abrupt, a bird 

 often reacting negatively one day and the opposite the next morning. If the hen is mated 

 promptly, it ceases almost immediately but otherwise may last for three to five days^. Un- 

 doubtedly additional matings often take place, particularly among renesting birds. Posturing, 

 on the part of a female, indicates she is in a receptive state. 



The exact manner by which the birds determine whether they are suitably matched is still 

 obscure. Nevertheless, it seems probable that the female, when in oestrus, seeks out the male 

 in his territory, probably most often in the vicinity of one of his drumming logs and that 

 the courtship performances which take place serve this purpose. If they are both in the 

 proper stage, mating takes place. If not, the hen retires, to return later or to move on to 

 another drumming male. 



The courtship performances of the male are discussed elsewhere in this chapter. Posturing, 

 as the characteristic behavior of the female in oestrus has been termed, is described by 

 Allen'" as follows: "The posture assumed by the receptive female is that of a stiffened, de- 

 pressed body with wings slightly spread and tail slightly raised"'. Among birds in captivity, 

 females in this condition will posture before an attendant, particularly if he extends his hand 

 over them. 



* See Chapter XI. p. 450. 

 A See Chapter U. p. 69. 

 t See Chapter U, p. 67. 



