Chap. 49.] 
THE SWALLOW. 
513 
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 Yergilise, 
and the summer and winter solstices ; when one is sometimes 
to be seen to hover about a ship, and then immediately dis- 
appear. 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 navi- 
gable, 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 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 sepa- 
rate, 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. OTHEE KINDS OF AQTJATIC BIEDS. 
The sea-mew also builds its nest in rocks, and the diver 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 INSTmCTIVE CLEVEENESS DISPLAYED BY 
BIRDS m THE CONSTRUCTIOI?' OF THEIR NESTS. THE WONDER- 
FUL 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, in- 
deed, 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 
This bird in reality builds no nest, hut lays its eggs in holes on the 
water side. The objects taken for its nest are a zoophyte called halcyonium 
by Linnaeus, as Cuvier informs us, and similar in shape to a nest. 
*2 Or didapper. 
VOL. II, L L 
