COURTSHIP OF THE GREAT CRESTED GREBE. 539 
2. The disposition of Y towards “ Y”; this is always more or 
less hostile, but there are variations (w) in the time at which the 
hostility is first shown, and (4) in the way in which it is shown. 
(a) Time. Y becomes hostile 
(i.) on passing near ‘‘Y,” although “‘Y” has been quite 
inactive ; 
(ii.) on passing near “ Y,” but only after ‘‘ Y ” has first gone 
into the hostile Dundreary attitude ; 
(111.) only when X (its mate) makes as if to approach “ Y” ; 
(iv.) only when its mate actually begins to shake with ** Y” ; 
(v.) only after its mate has shaken for some time with “ Y.” 
(b) Method. 
Y may (i.) simply swim at “Y”; 
(i1.) assume the hostile attitude and swim towards “ Y” ; 
(i11.) fly at ‘“ Y” along the surface of the water ; 
(iv.) dive and endeavour to come at ‘‘ Y” with the beak 
from below the surface. 
In addition, these actions may be gone through in succession ; 
if so, they are always gone through in this order, except that (iii.) 
and (iv.) may be reversed. ; 
3. The disposition of ‘‘ Y.” 
““Y” may be (a) simply indifferent to the presence of the pair ; 
(6) hostile to the pair ; 
(c) eager to “ flirt” with X. 
Here again the initiative may be taken (i.) by X, (ii.) by ‘“ Y.” 
Combinations of these pretty well exhaust the possibilities ; 
here I shall give an idea of the most usual happenings. 
When the two birds of a pair are swimming along together, 
and they pass close to a third bird, X usually takes no notice, 
and Y goes into the Dundreary attitude while passing “ Y,” 
sometimes swimming a little towards ‘“Y.” The odd bird, “ Y,” 
may be, and usually is, entirely indifferent to the pair, though it 
may adopt a threatening (Dundreary) attitude as a response to 
the similar threat of Y; and I once saw ‘“* Y” take the initiative 
in threatening. 
On the other hand, I have never seen any sign of a flirtation 
between X and the odd bird in these circumstances. 
That X should be willing or desirous to flirt with “ Y,” it 
seems necessary that its mate should either be absent or fairly 
distant, or, if close at hand, lethargic (see section 10, record 1), or 
unwilling to perform any courtship-actions. When a. flirtation 
does ensue, “ Y” may have taken the initiative, by swimming 
close up, calling, or going into the searching Dundreary attitude ; 
or X may have taken the initiative by swimming up te a 
Proc. Zoot. Soc.—1914, No, XX XVIII, 38 
