The magic peridens tree, keeper of the birds.
The one on the left is supposed to be from a 12th century English illuminated manuscript, the Aberdeen Bestiary; the one below is probably from a closely-related copy.
The text reads:
"The perindens is a tree in India. Its fruit is sweet throughout and exceedingly pleasant; doves delight in it and live in the tree, feeding on it. The dragon is the dove's enemy; it fears the tree and its shadow, in which the doves dwell; and it cannot approach either the tree or its shadow. If the shadow lies towards the west the dragon flees to the east, and if the shadow falls towards the east, the dragon flees to the west. If it should happen that a dove is caught out of the tree or its shadow, the dragon kills it...." (The rest of the text explains the religious metaphor.)