OCT. 1906. 
HERRING GULL AND CASPIAN TERN. 
131 
in a rapid jerky way, reminding one somewhat of the motions of 
a duck feeding in shallow water, at the same time emitting a 
peculiar chicken-like chatter. The other one immediatly joins in, 
apparently directing its attention to the same place on the ground, 
and the performance is kept up for a minute or two, when the 
birds straighten up ; perhaps to repeat the operation two or three 
times with short intermissions. There was no assignable cause 
for the performance and no observable result. Without any satis- 
factory clew, it was suggestive of having some relation to the 
selection of a site or the building of a nest. Two birds usually 
took part, one of my photographs apparently shows three, but 
whether or not these were pairs I could not tell. There was a lack 
of point to the affair that leads me to suspect that it may be a 
remnant of a more elaborate ceremony indulged in earlier in the 
season. 
Incipient nest building was going on continuously. There 
were, perhaps, half a dozen nests with fresh egfgs, but most that I 
collected contained large embryos. I saw no new nest making that 
seemed likely to be carried to completion, but observed a score or 
more of gulls picking up sedges and other materials, carrying 
them to some spot, frequently beside a log, and depositing them. 
Not infrequently one billful would be all that would be brought 
to that spot, and no farther attention would be paid to it after 
it was laid down ; but some gulls had a stronger trace of unsatis- 
fied nesting instinct (as Herrick had called it) and brought several 
loads to the same place and went through the motions of moulding 
the nest. This was accomplished by dropping the breast onto 
the gathered material and with the posterior part of the body 
tilted upwards and the feet straining, pushing it into shape with 
the breast. There seemed to be no attempt to arrange the material 
with the bill. Late in the evening one bird near my tent who 
had gathered three or four handfuls of rubbish spent some time 
moulding it, and then complacently sat upon the shapeless mass 
for several hours. 
Copulation occasionally, though rarely, took place on the island 
during my stay. I observed it three or four times. The prelim- 
inaries were short and were quickly followed by the female 
squatting slightly. The male then jumped upon her back, trod 
for some moments, then turned his tail sharply down and swung 
