caladrius, the story behind the name

According to the Aberdeen Bestiary (as well as earlier texts such as The Physiologus) the Caladrius is a snow-white bird that lives in kings' houses.

If it looks into the face of a sick man, it means that he will live, but if the caladrius looks away, the sick man will die of his illness. To cure the sick man, the caladrius looks at him, and drawing the sickness into itself, the bird flies away, dispersing the sickness and healing both itself and the sick person.

There are numerous theories as to where the legend of the Caladrius was started. One of them would be that it was created purely as an analogy of Jesus.

Another is that the Caladrius is based on a real bird. According to the descriptions of its being completely white with no black on it, it is possible that it was based on the dove, or possibly some sort of water bird such as the [heron] or the white wagtail, which have markings on their heads that resemble a skull, and are regarded in Ireland as mystical. See this page in the Aberdeen Bestiary: http://bestiary.ca/beasts/beast143.htm