COURTSHIP AND SEX 



i8i 



plumage leads to considerable mortality at man's hands, but 

 one is glad to know that the birds are not easily shot. Some 

 kinds have in both sexes special decorations put on at the 

 breeding season, such as crests and tippets of a golden 

 chestnut colour. In this respect, Professor Newton remarks, 

 the Eared Grebe (Podiceps auritus) is particularly remark- 

 able, " the head being surrounded, as it were, by a nimbus or 

 aureole, reflecting the rays of light, and glittering with a 

 glory that passes description." But it is the courtship 

 behaviour that is most striking, as Mr. Julian Huxley showed 

 some years ago in his careful study of the Great Crested 

 Grebe (Podiceps cristatus). (i) " Under the force of rising 



Fig. 36. — Courtship of Great Crested Grebe. (After Julian S. Huxley.) 

 The female in the so-called " cat attitude " of display. This is also 

 exhibited by the male. 



emotional tension " a bird waggles its head, first gently and 

 then violently ; the possible mate follows suit ; and a bout 

 of shaking ensues, interrupted at short intervals by a slow 

 side-to-side swinging and by curious backward bending of 

 the head as if to preen the wings. After a dozen Sr fifteen 

 violent shakes, with a corresponding number of slow swings 

 and liftings of the wings (" habit-preening "), the two birds 

 suddenly relapse into the normal. (2) A hen comes 

 swimming across the water, calling for a mate, on whose 

 appearance she suddenly assumes first a *' Dundreary " and 

 then a " cat " attitude, while he, appearing beside her after 

 a long " ghost-dive," " grows " up out of the water, standing 

 save for a few inches erect, like " the hypnotised phantom 

 of a rather slender penguin." He sinks slowly down again ; 



