98 BEHAVIOR OF PIGEONS. 



types of conduct distinctive of each sex; these may be termed masculine and 

 feminine traits. Each bird possesses its own distinctive sex-traits deeply and thor- 

 oughly ingrained in its organization. These tendencies function with a high degree 

 of readiness, ease, finish, and perfection. The organization of each bird also contains 

 in a more or less embryonic fashion the traits of the opposite sex. These tendencies 

 function only under unusual situations and the resultant behavior lacks the normal 

 degree of ease, vigor, and completeness of expression. The relative strength of the 

 two systems of tendencies varies with the individual, and we may say that male 

 birds differ in their degree of masculinity, while the females likewise vary as to 

 the dominance of feminine traits. 



These two systems are reciprocally related to each other at many points of 

 contact and hence are mutually exclusive in large part. They also differ as to the 

 stimuli to which they are susceptible. Aggressiveness, vigor, and determination 

 in demeanor and act tend to arouse the feminine traits, while submissiveness and 

 coyness make their natural appeal to the masculine tendencies. The type of 

 conduct manifested by any bird will thus be a function of the strength and nature 

 of its sexual impulse and the reciprocal behavior of its mate. In a natural mating 

 each bird will usually manifest the behavior distinctive of its sex. When the male 

 is temporarily exhausted from his endeavors the female may take the initiative 

 and perform the mounting. Often the sexual impulses do not develop synchronously 

 in a pair, and thus we may have a female dominated by passion mated with a 

 male who is in a state of relative unreadiness. In such a situation the female may 

 make the advances and possibly assume the masculine role in courting and copu- 

 lation. If incubation is defective in either bird, the mate will attempt to remedy 

 the deficiency by doing double duty. Unnatural matings are thus possible with 

 this conception. Each will attempt to act in a manner characteristic of its sex, 

 but when the acts are mutually exclusive a -contest will result and the bird with 

 the weaker sex-traits or with sex-traits nearest to those of the opposite sex 

 will be forced to play the role of the opposite sex. Since the degree of sexuality 

 is an individual variant, the same bird may play a different role in two unnatural 

 pairings. 



MATING PREFERENCES. 



The sexual activities are aroused by and are directed towards certain stimu- 

 lating objects. What is the nature of these stimuli, and what are the reasons for 

 their effectiveness? While no complete and final analysis of mating preference 

 is possible on the basis of these notes, Dr. Whitman's work establishes a few general 

 principles which determine sexual choice. 



Previous social environment is undoubtedly one factor. As a matter of fact, 

 pigeons normally pair with members of their own species, and this preference has 

 generally been regarded as instinctive in character. But the data of this volume 

 show rather conclusively that the species preferences exhibited by birds at maturity 

 are to a large extent acquired and are functions of the social environment in which 

 the birds were reared. We are told that young birds raised under foster-parents 



