Notes on the Ornithology of Caithness. S15 
sweep within reach, but their larger associate keeps far 
above, and seldom ventures within gunshot. On one of 
these stacks," situated in Sinclair's Bay, I have seen shags 
and cormorants sunning themselves in every niche, the top 
even being occupied by numbers of these sombre gentry. 
The black-back is extremely wild and vigilant, and conse- 
quently difficult to approach ; the only time when it ventures 
within reach of a gun, being in the breeding season, when 
it usually becomes a degree bolder. This gull is also very 
jealous of the neighbourhood of hawks and crows, having in 
especial an antipathy to the hooded crow. From its size 
and fierceness, it is generally monarch of all it surveys, the 
raven even succumbing to its attacks. In the last breeding 
season, however, the district received a visit from a stranger 
before whom all birds fled, the great black-back even making 
discretion the better part of valour. This was a white-tailed 
or sea eagle {Halicetus alhicilla), and his presence evidently 
caused the more alarm, from the fact that an eagle is seldom 
or never seen in the vicinity. An observer who carefully 
watched this powerful depredator while beating the margin 
of a loch not far from the edge of the rock, saw him slip 
over the precipice and shoot along about half-way between 
the top of the cliff and the sea. Hardly had he made his 
appearance, when a rush of birds seawards took place. 
Everything that could fly left the rocks, and the terror and 
confusion that ensued was remarkable. This continued 
during the whole course of his flight, and his appearance 
was invariably the signal for a hurrying of the scared masses 
out of the reach of danger. So numerous, and so very much 
frightened were the birds, that the progress of the eagle 
could be traced, long after he himself was invisible, by the 
strings of seafowl, of various kinds, that persistently con- 
tinued to seek safety in flight. It was long before gull and 
guillemot got over their fright, and matters resumed *' the 
even tenor of their way." ^ ' 
The Arctic skua, the lesser black-backed gull, and the 
common gull, breed in a remote moorland district in the 
centre of the county. Here there are numerous pools or 
patches of water, known as " doo-lochs," of various sizes 
and shapes, studded with mossy mounds or islands, which 
