COURTSHIP OF THE GREAT CRESTED GREBE. 495 
The three I have named, however, are those which the bird 
usually adopts. 
The ruff, therefore, may be :— 
(a) Depressed. 
(1) Shut tight (‘ gill-cover”). 
(2) At rest (relaxed), 
(b) Hrected. 
(3) Curtain-like (motion of feathers in one plane). 
(4) Pear-shaped 
(5) Elliptical 
By a combination of particular positions of ruff, ears, and neck, 
and sometimes wings and body too, the birds can assume a 
number of characteristic and often-recurring attitudes, which are 
the raw materials, so to speak, of all the elaborate habits of 
courtship. j 
Before giving any more definitions, I will now give an outline 
of the Grebe’s annual history, and then go on to describe some of 
the actual happenings that I saw, in order to give an idea of the 
problems to be solved. Then I shall try to define and classify 
the various courtship-habits, and discuss the general bearing of 
the facts. 
} (motion of feathers in two planes). 
3. ANNUAL History. 
This is somewhat as follows *. About the first week of 
February they leave the sea-coast and fly back in bands to the in- 
land waters where they breed. They live in flocks for about three 
weeks, and then start pairing-up. Pairing-up lasts altogether 
about a fortnight, bringing us to mid-March. From this time 
ou to the end of summer, the unit is neither the flock nor the 
individual, but the family, represented at first by the pair. 
About the beginning of April nest-building begins, and by the 
end of the month every nest will have eggs. The family parties 
live together through the summer, though apparently the cock 
leaves the hen to look after the young when they are half-grown 
(Pycraft, ’11). There is usually no second brood unless the first 
is destroyed. At the end of September they gather into flocks 
again, and live thus for well over a month, finally leaving for the 
sea-coast in the second week of November. 
The period of pairing-up itself I have unfortunately not been 
able to observe; the keeper tells me that there is much flying and 
chasing about. The part played by the “courtship” in the actual 
pairing-up is thus left uncertain. From analogy with other birds 
and with ourselves we should expect that the chasing was the 
expression of felt but unreasoned likes and dislikes, and that the 
courtship-actions were only gone through after the two birds had 
become fairly well-disposed towards each other. The courtship- 
* The dates refer to the movements of the birds at Tring Reservoir, and have 
been given me by the head-keeper there. 
