The Caladrius is a Roman mythological bird that lives in a kings house, and cleanses people of diseases, only if the Caladrius chooses. If it looks into the face of an ill person, it means that he will live, but if it looks away, the sickly person will die. To cure the person, the Caladrius looks at him, and drawing the sickness into itself, the bird flies up toward the sun, where the disease is burned up and destroyed. The Caladrius happens to be unclean, and is not to be eaten.
A Christian metaphor for the Caladrius is that it symbolizes Jesus, with being pure (all white) and takes away men's sins, like the way the Caladrius draws the sickness into itself and ascends upwards into the sun to destroy the disease(s).
"A mysterious bird that can tell the severity of one's illness as well as heal sickness itself. A Caladrius drew illnesses into itself with its beak and flew away, healing the sick. But if the sickness was too far advanced, the bird would refuse to even look at the sufferer. It is thought to be a plover or wagtail, but the only definite detail is that it is pure white."