410 THE ZOOLOGIST. 



and the singing of the Lark, and the dances of various birds, are 

 frequently placed in the same category as the display of plumage ; 

 but inasmuch as the Snipe performs his flight, and the Lark 

 soars and sings, after the young are hatched, I do not see how 

 such actions can be connected with the display used only for a 

 short period for the purpose of courtship. It is indeed a difficult 

 matter to discriminate between the display which takes place 

 during courtship and the display at certain periods after the 

 birds are paired. A display of this latter kind can frequently be 

 seen among many different species, especially among the Colum- 

 bidce. Wood-Pigeons, Stock-Doves, and Turtle-Doves raise 

 their tails, lower their heads, distend their throats, and utter a 

 peculiar cooing sound ; Finches go through a peculiar dancing 

 movement, but such actions as these must not be confused with 

 the display used preceding pairing. The fact that a large pro- 

 portion of the examples I have given belong to the Sylviince may 

 cause remark ; the reason is, that being specially interested 

 in the various species belonging to this order, and having ample 

 opportunities for watching, I have given them more attention. 



The advantages claimed by Mr. Darwin as likely to accrue to 

 the offspring of those males which proved through sexual selec- 

 tion attractive to the females, always appeared to me to constitute 

 a very great difficulty — a difficulty which does not usually appear 

 to have been fully recognized, although, as will be seen from the 

 following passage in the ' Descent of Man,' fully recognized by 

 Mr. Darwin himself. He says : — " Our difficulty in regard to 

 sexual selection lies in understanding how it is that the males 

 which conquer other males, or those which prove the most 

 attractive to the females, leave a greater number of offspring to 

 inherit their superiority than their beaten and less attractive 

 rivals. Unless this result does follow, the characters which give 

 to certain males an advantage over others could not be perfected 

 and augmented through sexual selection." Instances are brought 

 forward to prove that the courtship is of long duration. Such 

 instances are the leks of the Blackcock in Germany and Scandi- 

 navia, which last from the middle of March into May, and the leks 

 of the Capercailzie, which last from the end of March to the end 

 of May ; in North America the Partridge dances of Tetrao 

 phasianellus last for a month or more, &c. No evidence, however, 



