COURTSHIP OF THE GREAT CRESTED GREBE. 503 
take a particular case—that described by Selous on pp. 180-181 
of his paper :— 
About an hour earlier in the day there had been an attempt at 
pairing. Then, after a period of rest on the open water, the 
birds swam together towards the nest (which had been built 
the day before). When just outside the bed of reeds in which 
the nest was situated, the hen went into the passive attitude, 
on the open water. The cock came up to her, swam a few yards 
past her, went twice back to her and away again, then went 
right into the weeds and himself lay along the water in the 
passive attitude. While he was doing this (or immediately 
afterwards) the hen swam to the nest, leapt on to it, and sank 
down in the passive attitude once more. Upon this the cock 
came up to the nest, jumped on to the hen’s back, and they 
apparently paired successfully, both birds meanwhile uttering a 
special shrill screaming cry. 
Here are various points to be noticed. The joint approach of 
the birds to the neighbourhood of the nest is invariable when 
they have previously been some distance away. When one bird 
is sitting, or when both are already close to the nest, as when 
building is in progress, the case is of course different (p. 533); 
but in the period between nest-building and incubation they 
seem never to approach the nest singly. 
The passive attitude on the open water close to the weeds and 
nest may or may not be assumed. In the three cases where 
this happened and Selous is absolutely sure of his facts, the bird 
that assumed this position was the female, and was also the 
leader in the procession towards the weeds. (We want to know 
more about this. It seems probable, from other considerations, 
that it is a mere coincidence for the leader to have been always 
the hen; but, this being granted, it is quite likely that the 
leading bird would be the more eager, and so would hasten to 
put itself into the attitude which apparently expresses readiness 
to pair.) In other cases the birds swam straight to the nest, 
and one of them ascended it and then went into the passive 
position. 
Next, the way in which the cock swam about close to the hen 
while she was in the passive attitude, but still on the open water, 
“as though about to pair” (I quote Selous), is interesting. 
There must be a strong association established between the sight 
of the passive attitude and the desire to pair, so that the active 
bird shows its thoughts, so to speak, even when pairing is 
impossible (as when the passive bird is on the open water). 
When the passive bird has gone into position on the nest, it is 
very nearly always the case that the active bird comes up to the 
passive one and examines it or swims about a bit, whether an 
attempt to pair is afterwards made (Selous, ’01, pp. 180, 345) or 
not (loc. cit. pp. 165, 344, etc.). Sometimes the second bird is not 
eager, and refuses to come near at all (¢. 9., loc. cit. pp. 172, 456). 
At other times (loc. cit. p. 341, and perhaps p. 181) an attempt 
