24 
Proceedings of the Koyal Society of Edinburgh. [Sess. 
and bays which border the northern shores of the Pentland Firth. In 
these waters the marine birds are very abundant, particularly the guillemot 
and the shag. The cormorant appears to be somewhat scarce, and the 
different species of the sea-gull, although numerous, are very wary and not 
easily approached. 
No attempt was made to catch the birds alive, since it was recognised 
that the excitement immediately following capture and the violent move- 
ments which they would certainly make in their attempts to regain freedom 
would, even in a few minutes, produce a distinct rise in the body tempera- 
ture. They were shot dead at close range and the thermometer introduced 
into the rectum, usually in less than half a minute, and frequently within 
a few seconds, after death. In this short interval it is assumed that no 
appreciable loss of heat from the body took place, and that the figure 
recorded indicates the rectal temperature immediately before death ; at all 
events, it is pretty certain that any error introduced by this method would 
be much smaller than what would be found if the birds had been captured 
and handled alive. 
The shooting was done for the most part from a small sail-boat, in a 
smooth sea, and with a light breeze of wind. The stalking of these birds 
in the water requires some skill on the part of the boatman, since they are 
very watchful and readily take alarm. The shags and guillemots are 
almost always seen in the water, where they swim and dive to perfection. 
In flight the wings are moved rapidly, after the manner of the duck tribe, 
and one always has the impression that the bird is making a great effort 
in maintaining itself in the air. Considerable difficulty is experienced 
in starting; they flap along the surface of the water for some distance, 
and fill their wings preferably by rising into the air against the wind, 
and advantage is taken of this fact in getting within short gunshot range. 
The shags usually fish in small flocks of from two to six or eight, or 
more ; and when such a flock is sighted, the boat is steered, not straight for 
the birds, but to the windward side of them, and at such a distance as not 
to cause them to take alarm. Then the course is suddenly changed and 
the boat is held before the wind directly for the flock. When danger is 
scented the shag usually seeks escape by flight, not by diving, and in rising 
from the water against the wind it meets the boat, and is shot dead at close 
range. I mention this to show that the birds were not chased before being 
killed. Those that succeeded in diving after being wounded, and required 
to be followed up and killed by a second shot, are not included in the 
subjoined tables. No wounded bird was allowed to escape. 
Practically all the birds were killed with the first shot and picked up 
