Sources : Jay

Ovid [1st century CE] (The Metamorphosis, Book 5, 642-678): The Emathides laughed and ridiculed these threatening words, but as they tried to speak, and attack us with insolent hands, making a great clamor, they saw feathers spring from under their nails, and plumage cover their arms. Each one saw the next one’s mouth harden to a solid beak, and a new bird enter the trees. When they wanted to beat their breasts in sorrow, they hung in the air, lifted by the movement of their arms, magpies now, the slanderers of the woods. Even now, as birds, their former eloquence remains, their raucous garrulity, and their monstrous capacity for chatter. - [Kline translation]

Aelianus [170-230 CE] (On the Characteristics of Animals, Book 6, 19): Now the jay can imitate all other sounds but especially the human voice. - [Scholfield translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.61): Garrulus, as Isidore says [Isidore was actually describing the jackdaw, gracculus, not the jay, garrulus.], was named from garrulita [garrulous, talkative]. For it is a most talkative kind of bird, and is importunate in its voices. It passes from one place to another while chattering, and hardly anyone can pass it without it chattering. It imitates the voices or songs of other birds, not for the sake of delicious delight, but for chattering. This bird, taken in its youth, is caged so that it may be taught to speak articulate words, and when it has escaped, it tends to chatter more. But it sometimes happens that, while it is not looking out for itself and is intent on chattering, the sparrowhawk [nisis] unexpectedly seizes it. This bird is distinguished by such a variety of plumage that it is said to not lack any of the colors of other birds. It is said that it often goes mad, so that the Experimentator says that it hangs itself in a tree between the forked branches in a fit of rage. - [Badke translation/paraphrase]