(30.) The blackbird is found in the vicinity of Cyllene, in Arcadia, with white[3012] plumage; a thing that is the case nowhere else. The ibis, in the neighbourhood of Pelusium[3013] only is black, while in all other places it is white.
CHAP. 46. (31.)—THE TIMES OF INCUBATION OF BIRDS.
The birds that have a note, with the exception of those previously mentioned,[3014] do not by any chance produce their young before the vernal or after the autumnal equinox. As to the broods produced before the summer solstice, it is very doubtful if they will survive, but those hatched after it thrive well.
CHAP. 47. (32.)—THE HALCYONES: THE HALCYON DAYS THAT ARE FAVOURABLE TO NAVIGATION.
It is for this that the halcyon[3015] is more especially remarkable; the seas, and all those who sail upon their surface, well know the days of its incubation. This bird is a little larger than a sparrow, and the greater part of its body is of an azure blue colour, with only an intermixture of white and purple in some of the larger feathers, while the neck[3016] is long and slender. There is one kind that is remarkable for its larger size and its note; the smaller ones are heard singing in the reed-beds. It is a thing of very rare occurrence to see a halcyon, and then it is only about the time of the setting of the Vergiliæ, and the summer and winter solstices; when one is sometimes to be seen to hover about a ship, and then immediately disappear. They hatch their young at the time of the winter solstice, from which circumstance those days are known as the “halcyon days:” during this period the sea is calm and navigable, the Sicilian sea in particular. They make their nest during the seven days before the winter solstice, and sit the same number of days after. Their nests[3017] are truly wonderful; they are of the shape of a ball slightly elongated, have a very narrow mouth, and bear a strong resemblance to a large sponge. It is impossible to cut them asunder with iron, and they are only to be broken with a strong blow, upon which they separate, just like foam of the sea when dried up. It has never yet been discovered of what material they are made; some persons think that they are formed of sharp fish-bones, as it is on fish that these birds live. They enter rivers also; their eggs are five in number.
CHAP. 48.—OTHER KINDS OF AQUATIC BIRDS.
The sea-mew also builds its nest in rocks, and the diver[3018] in trees as well. These birds produce three at the very most; the sea-mew in summer, the diver at the beginning of spring.
CHAP. 49. (33.)—THE INSTINCTIVE CLEVERNESS DISPLAYED BY BIRDS IN THE CONSTRUCTION OF THEIR NESTS. THE WONDERFUL WORKS OF THE SWALLOW. THE BANK-SWALLOW.
The form of the nest built by the halcyon reminds me also of the instinctive cleverness displayed by other birds; and, indeed, in no respect is the ingenuity of birds more deserving of our admiration. The swallow builds its nest of mud, and strengthens it with straws. If mud happens to fail, it soaks itself with a quantity of water, which it then shakes from off its feathers into the dust. It lines the inside of the nest with soft feathers and wool, to keep the eggs warm, and in order that the nest may not be hard and rough to its young when hatched. It divides the food among its offspring with the most rigid justice, giving it first to one and then to another. With a remarkable notion of cleanliness, it throws out of the nest the ordure of the young ones, and when they have grown a little older, teaches them how to turn round, and let it fall outside of the nest.
There is another[3019] kind of swallow, also, that frequents the fields and the country; its nest is of a different shape, though of the same materials, but it rarely builds it against houses. The nest has its mouth turned straight upwards, and the entrance to it is long and narrow, while the body is very capacious. It is quite wonderful what skill is displayed in the formation of it, for the purpose of concealing the young ones, and of presenting a soft surface for them to lie upon. At the Heracleotic Mouth of the Nile in Egypt, the swallows present an insuperable obstacle to the inroads of that river, in the embankment which is formed by their nests in one continuous line, nearly a stadium in length; a thing that could not possibly have been effected by the agency of man. In Egypt, too, near the city of Coptos, there is an island sacred to Isis. In the early days of spring, the swallows strengthen the angular corner of this island with chaff and straw, thus fortifying it in order that the river may not sweep it away. This work they persevere in for three days and nights together, with such unremitting labour, that it is a well-known fact that many of them die with their exertions. This, too, is a toil which recurs regularly for them every year.