I posted a free-floating meme for a laugh and ended up learning something new. This illustration from a medieval manuscript isn't a tucking-in bird, it's a caladrius. The caladrius bird was usually white, and often lived with kings. A medieval healer would be well-equipped to own, or at least know, a caladrius because of their healing and diagnostic abilities.
The dung of the caladrius was believed to cure blindness, but this remedy was rather a mixed blessing since it required the direct application of guano in the eyes of the afflicted. But the real value of the caladrius was in its infallible prognostic abilities. If it was brought into a sickroom and turned away from the man or woman within, that person would surely die. If, however, the caladrius kept his gaze on the ill person and 'directed itself towards his face' (sometimes this is depicted quite literally; see below), it was a different story. After staring down the sick man or woman, the caladrius would fly into the air, taking the illness with it, and the patient was destined to make a full recovery.
You rarely see any depictions of a caladrius bird after the 15th century, but Saturday Night Live featured one in a skit called Theodoric of York.
See more illustrations of the caladrius and you can learn something new, too, at the British Library's Medieval Manuscripts blog. -Thanks Kolo Jezdec!