Chap. 42 The Various Kinds of Birds Which Afford Omens by Their Note — Birds Which Change Their Colour and Their Voice
There is another remarkable fact too, relative to the birds which give omens by their note; they generally change their colour and voice at a certain season of the year, and suddenly become quite altered in appearance; a thing that, among the larger birds, happens with the crane only, which grows black in its old age. From black, the blackbird changes to a reddish colour, sings in summer, chatters in winter, and about the summer solstice loses its voice; when a year old, the beak also assumes the appearance of ivory; this, however, is the case only with the male. In the summer, the thrush is mottled about the neck, but in the winter it becomes of one uniform colour all over.