Thomas of Cantimpré, Liber de natura rerum [circa 1200-1272 CE] (Birds 5.68): We call the isida bird by the sound of its voice. It is indeed a small bird, but the beauty of its feathers is very bright. On the back it has a color between green and cerulean, so beautiful that if it is illuminated by the sun's rays from the opposite side, you will see that it has a sapphire appearance in its feathers. But the color which is in the breast is like burning coals. it has only two toes on its foot with hooked claws, but a small and straight face. It lives on small fish and is constantly around the water. With its beak it digs holes in the ground, where it builds a nest and makes offspring. About this bird the common people - and whether they think true or false, I do not know - because if you take off the skin with the feathers of a dead bird and stick it to the wall, every year the feathers of the skin will change, as if it were on the body. ... And it signifies those who refused to abandon their bad manners and old customs while living, whom the dead will certainly change, because for pleasure they will obtain punishment, for vain joys pain, for transitory evils eternal hell. - [Badke translation/paraphrase]