.COURTSHIP ACTIVITIES IN THE RED-THROATED DIVER. 261 
successful, but this is hard to judge). He then walked up her body and off 
her right shoulder (in this whole action behaving very much like the Crested 
Grebe)." 
The female remained perfectly motionless for one or two minutes in the 
same extended position ; the male, after sitting on the bank for a sliohtly 
less time, took to the water. The female than sat up, plucked up pieces of 
moss as before, but fewer and with less energy, and then joined hor mate on 
the water. After swimming, with the male leading, they turned ; the female 
gave a short flight of a few j^irds, the male swimming rapidly after her ; the 
male then gave a similar short flight. Both shook their heads emphatically 
several times (compare the Crested Grebe). After a short time the female 
got up, followed at once by the male, and both flew off westwards and were 
lost to sight. This abandonment of the nest with an egg in it was remark- 
able ; possibly they were more upset by the presence of the tent than they 
appeared to be. In any case, apart from the presence of a pair of birds 
which may or may not have been the same, for a short time next day, the 
tarn was abandoned, and the egg fell a prey to Skuas within 24 hours. 
Another nest was discovered on a neighbouring tarn on July 7. This 
already contained two eggs, although this tarn had been still later inthawino- 
than the other, and had ice extending for some distance in from all its 
margins on July 2. This tarn was within a short distance of camp, and 
the " roll-grovrl," signifying the mutual "snake-ceremony,'" was frequently 
heard from it (e. g. 5.30 a.m. July 9). This shows that mutual "courtship" 
continues, as in the Grebe, throughout the incubation period. On investi- 
gating the banks, a " cock's nest," similar to the one already described but. 
rather more rudimentary, was discovered, also on a rather mossy part of the 
shoi'e (as a matter of fact, the only mossj' part in this tarn) ; doubtless it, too 
subserved the function of coition. 
The association of the mossy bar with the rudimentary nest is interestino-. 
The true nest often contains some moss ; and the behaviour of the female, 
above recorded, in plucking up moss from the bank shows that in the Diver, 
as in many other birds, the handling of nest-material has a sexually 
emotional association. It is presumably this emotional association which 
prompts the choice of a mossy bank as the site of the pairing-nest. There is 
however, far less nest-material employed than by tlie Grebes ; and 
accordingly nest-material plays a smaller part in the Divers' sexual, 
ceremonies. 
On my arriving at the hiding-tent on the evening of July 9, the female, 
who was sitting, was rather suspicious, left the nest, and swam about 
restlessly on the pool for some time. Although alone, she frequently dipped 
her head half into the water, as jirevioiisly described, for 5 to 15 seconds. Thus, 
this habit, which is undoubtedly the main " as?ociational" habit of this 
species, may be associated with other emotions than that of sexual excitement — - 
