26 
Proceedings of the Royal Society of Edinburgh. [Sess. 
secured in the Orkneys struggled violently when captured, and the tempera- 
ture was not recorded till some hours afterwards, when it had become 
somewhat accustomed to its surroundings. 
While on a voyage from New York to Liverpool on the R.M.S. 
Mauretania, a storm-petrel ( Procellaria pelagica), attracted by the lights, 
flew on board and was caught on the deck. This was at 10.30 p.m. on 
July 24, 1908, in N. latitude 41° 58', W. longitude 46° 22' — that is, in the 
North Atlantic, about mid-ocean. The rectal temperature was taken, and 
found to be only 103 o, 6 F. (39 0- 8 C.). The bird was then set at liberty. 
The temperature of the air and of the sea at the time was in the neighbour- 
hood of 70° F. (21° C.). Another specimen came on board about the same 
time, but flew away again before it could be secured. 
In the spring and autumn of 1909 one grebe and a few wild ducks of 
different species were shot on and in the vicinity of Lake Cayuga, in the 
western part of the State of New York, and the rectal temperature taken 
in the usual way. After the winter migration south, from October or 
November on to April or May, large numbers of wild ducks frequent this 
and the neighbouring lakes, but they are very difficult to approach and 
comparatively few were obtained. They were killed either while swimming, 
or flying immediately after having risen from the water. 
In the cormorant, shag, guillemot, and sea-gull the sexes are alike in 
7 o 7 o 7 o 
plumage, so far as I know, and cannot be easily distinguished without 
dissection, unless possibly by an expert ornithologist. In a number of 
cases, however, the birds were marked and the sex determined later by 
post-mortem examination, but this could not always be done. The six 
specimens of the solan goose taken from the nest were probably females. 
In all species of the duck tribe the male is more brilliantly marked than 
the female, and there is no difficulty in telling the one from the other. 
The results obtained are presented in the following tables : — 
