COURTSHIP OF THE GREAT CRESTED GREBE. 497 
preening, but had an extraordinary look, as of a stereotyped 
and meaningless relic. The birds seemed to be performing some 
routine-action absent-mindedly and by mere force of association, 
as one may sometimes see a man wind up his watch in the day- 
time, just because he has been changing his waistcoat. 
Finally, after each bird had given about a dozen or fifteen 
violent shakes, with a corresponding number of slow swings and 
liftings of wings in between, they veered up into the wind almost 
simultaneously, lowered their crests, brought their necks down, 
and, in a word, became normal once more both in appearance and 
behaviour. 
One must have names for things if one is going to discuss them, 
as any philosopher will tell you. So I propose to call a whole 
performance such as that just described a bout of shaking; each 
little time of violent wagegling I shall call simply @ shake, and 
shall measure the length of a bout by the number of shakes in it 
(counting the shakes of both birds added together). Finally, the 
curious actions resembling preening I shall call habit-preening, 
because I believe them to have (or rather, to have had) something 
to do with real preening, but, in the per formance as gone through 
to-day, to have "eCoUne & : mere habit, vestigial so far as its or iginal 
function is concerned. 
(5) That is one little seene: now take another. 
A solitary bird, which proved to be a hen, came flying over from 
one reservoir to another. She alighted near one shore and began 
swimming slowly across towards the other, meanwhile alternating 
between two attitudes. 
First of all she arched her neck right forward till the bill, 
which pointed slightly downwards, was just above the water. 
The ears meanwhile were scarcely erected ; the ruff was thrown 
forward in curtain-form, and thus, since the head had been 
brought so far forwards and downwards, actually swept the 
water on either side (fig. 3). So she progressed, looking from 
side to side, and now and then giving a short barking call. 
After four or five of these calls, which represented perhaps 20 or 
30 seconds of time, she put down her ruff and raised her neck 
nearly straight up to enlarge her circle of vision. 
After some seconds of looking about her in this position, she 
relapsed again into the first attitude—‘ with neck outstretched, 
you fancy how.” This was repeated eight or nine times, til at 
last a cock, thirty or forty yards away, appeared to notice the 
ealling bird. He pricked up his neck, looked towards her for a 
short “une. and then dived. At eh she changed her whole 
demeanour. Up went her wings: back hebween them, with 
erected ruff and ears, went her head. A glance at fig. 7 will 
show her attitude. The wings were brought up, half- spread on 
either side of the body, with their antorion border pointing down- 
wards. They were almost in the transverse plane, but sloped 
slightly backwards from the water. 
