COLOR AND .SEX. 



45 



exact value remains to lie determined by closer ol)Ber- 

 vation. 



Color and Sex.''' — It is not pos.sible here to discuss at 

 length the vexed question of sexual coloration. But, as a 

 nieuiis of directing observation, I present a synopsis of 

 the principal types of secondary sexual characters, with 

 some of the theories which have Ijeen advanced to ac- 

 count for them. 



SYNOPSIS OF THE SECONDARY SEXUAL CHARACTERS 

 OP BIRDS. 



Size. 



Plumafre. 



Of the body. 



Of the feet. 

 Of the bill 



I. STRUCTURAL. 



J Male lai'fi-er than female (usual). 

 ( Female larger than male (rare). 



Hale brighter than female. 

 Female Ijrighter than male (rare). 

 ' Assumption of plumes, niifs, crest.s, trains, 

 etc. : special modification of wing and tail 

 feathers. 



Worn by nuale alone. 

 [ b. Worn by both sexes. 

 Sole or greater development in male of brightly col- 

 ored bare tracts of skin, combs, wattles, caruncles, 

 and other fleshy or horny appendages. 

 Sole or greater development in male of spurs. 

 Blale with more highly colored or larger bill than 

 female. 



Color. 



Fori 



Pursuit. 



Display. 

 Battle. 



Music. 



Special 

 habits. 



II. FUNCTIONAL. 



( By male when similar to or brighter than female. 

 \ By female when brighter than male. 



By male of accessory plumes and other appendages. 



By male using spurs, wings, bill, etc. 

 ( Vocal, by male and. rarely, female. 

 I Mechanical, by male and sometimes female. 

 f Dances, mock fights, aerial evolutions, construction of 

 I bowers, decoration of playgrounds, attitudinizing, 

 \ strutting, etc. 

 I (I. By male before the female. 

 I b. Among the males alone. 



* Read Darwin, The Descent of Man and Selection in Relation to 

 Sex (D. Appleton & Co.). W^allace, Darwinism (Macmillan Co.). 



