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SOME POINTS IN THE SEXUAL HABITS OF THE 

 LITTLE GREBE, WITH A NOTE ON THE 

 OCCURRENCE OF VOCAL DUETS IN BIRDS. 



BY 



J. S. HUXLEY. 



During April, 1919, I had an opportunity of seeing something 

 of the habits of the Little Grebe or Dabchick {Podiceps r. 

 ruficollis). Although my observations do not pretend to 

 completeness, they are of some interest if taken in comparison 

 with the more fully-known habits of a related species, the 

 Great Crested Grebe (Huxley, Proc. Zool. Soc. 1914). 



In this latter species it has been possible to distinguish 

 three quite separate forms of sexual actions — those taking 

 place at the time of pairing-up, those connected with the act 

 of coition, and self-exhausting ceremonies performed by both 

 birds of the pair together after pairing-up. In the second 

 class of ceremonies the sexual adornments (ruff, ear-tuft, 

 etc.) are never employed, while in the third class they always 

 are. The ceremonies of the third class are mainly mutual, 

 the actions being identical in both male and female ; but 

 there are a few, more rarely performed, where the roles of 

 male and female are dissimilar ; and one which is entirely 

 unisexual, performed by one bird only. 



The season was too late for the observations of the pairing- 

 up actions in the Dabchick ; I am not aware of their having 

 been elsewhere recorded. Ceremonies of the second class 

 I was not able to see. If they exist, in all probability they 

 take place among thick reeds near the nest. It was only 

 ceremonies of the third class that I had the opportunity of 

 observing. 



The Dabchick shows a seasonal change of plumage, the 

 colours and patterns of the head becoming more striking 

 for the nesting season. It differs, however, from all the other 

 British species of the family in never possessing any tufts, 

 crests, or frills on the head. It is therefore interesting to 

 find that the common form of mutual ceremony in this 

 species depends not on visual stimulation as in Podiceps 

 cristatus, but on an auditory stimulation. It is in fact a 

 duet, performed together by both birds of the pair. 



The note of the Dabchick is very startling, consisting of 

 a long shrill peal, somewhat like the neigh of a horse trans- 

 posed into a very high region of the scale, and mixed with 

 some wildness and a certain quality of laughter. This note 

 may be given by a single bird, but it is more often heard as a 



