Davis and Domm i^o 



not show such intense Hbido and did not run as rapidly toward introduced fe- 

 males. There was no crowing or "tidbitting." A very weak "waltz," consisting 

 merely of lowering the wing, occurred occasionally. "Waltzing," which is used 

 by the male to induce the newcomer to indicate its sex by either squatting 

 (female) or raising the neck hackle (male), consists of a lowering of the wing 

 nearest the newcomer and a kicking of the leg on the same side against the 

 lowered wing. It must be remembered that "waltzing" does occur, although 

 rarely, in capons which appear to be devoid of testicular tissue. "Tidbitting" 

 is a characteristic coaxing, clucklike call accompanied by pecking at or tap- 

 ping the ground or floor of the pen with the beak, which usually holds a 

 morsel. This pattern is a substitute behavior, usually observed when a male 

 is frustrated in his attempt to copulate. 



Since the effect of estrogen in causing the capons to copulate was heterodox, 

 another series was begun in order to check the results. As indicated in the 

 table, three birds were injected with a-estradiol and three with stilbestrol. 

 Of the estradiol birds, i6gRY copulated on the sixth day, igsYY on the fifth 

 day, and 193MY on the fourth day of injection. Of the stilbestrol birds, 

 382MM copulated on the fourth day, and igoYY on the fifth day. 191RR 

 was a very nervous bird and never copulated. Sexual libido normally mani- 

 fested itself in the estrogen-injected capons by their frequent attempts to tread 

 one another, which occasionally succeeded, as for example when 382MM 

 raped 191RR on the afternoon of November 5. When a female was released in 

 the pen with all the capons, a veritable melee resulted from the attempts of the 

 birds to copulate. There is a possibility that the capons became refractive 

 to estrogen, for some of the birds which had copulated regularly did not 

 copulate in the last few trials at the end of the experiment. 



When exposed to a normal rooster the estrogen-injected capons invariably 

 fled. They never squatted for copulation and were unreceptive and struggled 

 whenever the rooster forced copulation. 



The position of the dummy is important in the reaction of the estrogen- 

 injected capon. If the dummy is facing him, he raises the hackle and begins 

 to fight. If, on the other hand, it is not, he copulates. For example, on October 

 24, capon 170Y which had received 0.50 mg. a-estradiol daily for thirty-three 

 days approached the dummy from the front, raised the hackle, and pecked 

 the head. In walking away he happened to circle the dummy. He then ap- 

 proached it from the rear and copulated. 



3. The Effect of Estrogen in the Rooster. The two normal roosters which re- 

 ceived stilbestrol gradually lost their aggressiveness and stopped crowing on 

 the tenth day of injection. Nevertheless, copulations continued to the end 

 of the experiment (47 days). The behavior pattern was complete but was per- 

 formed in a lethargic, listless manner. The comb decreased practically to the 

 castrate condition in each, and when autopsied on August 5 the testes of both 

 were in a markedly regressed condition (macroscopically), weighing 75 and 

 110 gm. per bird. A third bird became sick soon after the start of the expcri- 



