The ROCK SWALLOW (_Cotyle rupestris_) is about five inches and a half
long, and from twelve and a half to thirteen and three-quarters broad;
the wing measures about five inches. The coloration of the plumage
closely resembles that of the rocks upon which this species principally
lives. The upper parts of the body are light brown, the quills and tail
blackish; the centre feathers that compose the latter are beautifully
marked with oval yellowish white spots; the throat is whitish; the breast
and belly dirty reddish grey; the eye is dark brown, the beak black, and
the foot reddish grey. The sexes are nearly alike; the young are somewhat
more uniform in hue than the adult bird.
The actual habitat of the Rock Swallows appears to be Spain, Italy, and
Greece, but they are constantly met with and are known to breed in the
Tyrol, and even in still more central parts of Europe. So hardy are
they that such as migrate do not leave till the autumn is far advanced,
and return as early as February or March; whilst others, inhabiting
the extreme south, remain in their native land throughout the entire
year. In Egypt and South-western Asia they are replaced by a smaller
but very similar species. The Rock Swallows seldom associate with their
congeners, and are readily distinguished from them by their greyish hue,
and comparatively slow and hovering flight. In Switzerland, after their
return in the spring, they usually allow some time to elapse before they
seek their own nests or build new ones; during the interval they busy
themselves in making excursions in all directions, either skimming near
the mountains, or, if the weather be fine, soaring to a considerable
height in the air. If, on the contrary, the season be dull or rainy, they
keep close to the earth, or beneath projecting rocks and stones. If the
day be bright, they come down from their retreats among the mountains,
and perch upon the roofs of cottages, but never venture actually into
houses. The nest is placed beneath a projecting ledge of rock, or in some
similar situation, and resembles that of the Chimney Swallow. Several
pairs frequently build together, but we have never seen settlements
like those formed by some other species. Many various statements have
been made as to their mode of nidification, seeing that, owing to the
precipitous nature of the localities selected, it is very often extremely
difficult to approach the abode of a Rock Swallow. The eggs are white,
spotted with red, and are from three to five in number. After the
nestlings are fully fledged, they still remain for some time with the old
birds, following them about in search of insects, which are caught on the
wing, but as soon as a fly or a beetle is thus obtained, the hungry young
perch for a moment upon a tree, and receive the morsel from the parent's
beak. When the period of incubation is over, the different families form
small parties, and wander about the country, as in the spring, until the
proper time for commencing their migrations. In its general disposition,
the Rock Swallow is less alert and brisk than its congeners, and its
voice has a deeper and rather hoarse sound.