1. As the actions of all animals agree with their dispositions, so also
their dispositions will change with their actions, and some of their
parts also. This takes place among birds; for hens, when they have
conquered the cock, desire to copulate with others, and their crest
and rump become elevated, so that it is difficult to say whether they
are hens or not. In some, also, small spurs are found; and some males,
after the death of the female, have been seen to take the same care
of the young as the female would have done, leading them about and
feeding them, and neither crowing, nor desiring sexual intercourse. And
some male birds have been seen to be so effeminate from their birth,
that they neither crowed, nor desired sexual intercourse, and would
submit themselves to any males that desired them.
3. Many birds at particular seasons change both their colour and their
voice, as the blackbird, which becomes russet instead of black, and
assumes another voice, for it sings in the summer time, but in winter
it chatters and screams violently. The thrush also alters its colour,
for in winter it is grey, and in summer is variegated on the neck;
but its voice does not alter. The nightingale sings unceasingly for
fifteen days and nights, when the mountains become thick with leaves.
As the summer advances it utters another voice, not quick and varied,
but simple; its colour also is altered, and in Italy it is called by
another name at this season of the year. It only shews itself for a
short time, for it lies concealed.
3. The erithacus, and the bird called phœnicurus, are changed one
into the other. The erithacus is a winter bird, the phœnicurus a
summer bird; they differ in nothing but the colour. The sycalis and
melancoryphus are the same, for these also are interchanged. The
sycalis is found in the autumn, and the melancoryphus immediately after
the end of the autumn. They also differ from each other in nothing but
their colour and voice, and to prove that it is the same bird, each
kind has been seen immediately after the change took place; and when
the change was not quite complete, there was nothing characteristic of
either form. Nor is it absurd to suppose that these birds change their
voices or their colours, for the dove utters no sound in the winter,
unless it may be on a fine day in a severe winter, when it will utter
its sound to the astonishment of those that know its habits; and as
soon as spring commences, it begins to utter its voice: and, on the
whole, birds make the greatest number and variety of voices at the
season of coition.
4. The cuckoo also changes its colour, and its voice is not distinct,
when it is about to leave us. It goes away about the time when the
dog-star rises, it having been with us from the commencement of spring
to that time. The œnanthe, as it is called, disappears when Sirius
rises, and comes again when it sets, for sometimes it retreats before
the cold, and sometimes before the heat. The hoopoe also changes its
colour and its forms, as Æschylus writes. "He had variegated this
hoopoe, the witness of its own evils, and has displayed the bold bird
that dwells in the rock in all armour. In the early spring it shakes
the feathers of the white hawk; for it has two forms, that of the
young bird and of itself, from one origin. And when the young corn of
the harvest begins to grow, it is clothed in spotted feathers; and it
always hates this place of Pallene, and inhabits deserted forests and
mountains."
5. Some birds dust themselves, and others bathe. Some neither dust nor
bathe. Those that do not fly, but live on the ground, dust themselves,
as the domestic fowl, partridge, grouse, lark, and pheasant. Those
birds which have straight claws, and live near rivers, marshes, and the
sea, bathe themselves. Some, like the pigeon and sparrow, both dust
and bathe. Most of those with crooked claws do neither the one nor the
other. This is their nature in these matters. The act of breaking wind
backwards is peculiar to some birds, as the turtle. Such birds make a
strong motion with their rumps when they utter their voice.