152 Huxley, Bird-watching and Siological Science. [April 



courtship, elaborate Courtship-actions gone through by both sexes, 

 as a form of enjoyment (Hke a dance) . We have Engagement and 

 Seasonal Marriage, not exempt from Flirtation; we have special 

 Coition Ceremonies, again shared equally by both sexes. We have 

 in fact a Courtship which to one, like myself, who was familiar only 

 with the facts adduced by Darwin and his followers, was a complete 

 revelation — something entirely new and unexplained. 



We will now turn to a modern investigation of a species which 

 has figured prominently in the sexual selection doctrine from 

 Darwin's time to the present. In the Blackcock (Tetrao tetrix, 

 fam. Tetraonidse) Selous ^ has made a series of careful observations, 

 which show how totally different is the series of events in a species 

 which exhibits marked sexual dimorphism combined with polygamy. 

 The main unquestioned facts may be briefly stated. The cock 

 birds are magnificent in a plumage of sheeny bluish-black with 

 beautiful lyre-shaped tail. On the wing and tail are patches of 

 pure white, while over the eye is a streak of scarlet. The female is 

 so different as to merit a distinct name, the Greyhen; she is much 

 smaller and of a dull reddish brown color speckled with black — 

 a purely protective scheme of coloration. In these birds the pair 

 does not exist as a unit. In April and May the cocks assemble early 

 in the morning at regular meeting-places and go through various 

 remarkable courtship-actions. The hens visit these assembly- 

 grounds, and there coition takes place, several hens often mating 

 with one cock. These are the main facts ; their interpretation, as 

 always, has depended on the closest watching of the details. Selous 

 finds that what really happens is as follows. The cocks have defi- 

 nite stations or territories of their own on the assembly-ground, 

 which they do not leave except under the influence of violent 

 excitement, such as jealousy. Their actions fall into three main 

 categories : — the ecstatic dance, not executed specially before the 

 hen; a display performed directly to the hen and battles (which, 

 however, are in reality but jousts, or sham-battles) between cocks. 



The dance has often been described; at its most violent, it must 

 be an amazing spectacle. The tail is spread out and erected, the 

 wings a trifle drooped, the head alternately raised and lowered. 



1 Selous CO'J). 



