The ancient legend of the pelican  was adopted into Christianity by the 2nd century, when it appears in the Physiologus, a Christian adaptation of popular animal legends and symbols.

The Pelican nourishes his children with the blood of his heart.

He still lives at the shore of the big quieted sea of Samsara.

The Pelican is often looked at as the Lapis, which consumes itself during the . (Waltharius 1956) (truer : Multiplicatio)

Later it became a symbol of esoteric  freemasonary as of the  "18° Knight of the Rose Croix" Scottish Rite.b

Other pictures show a single pelican who just stands beside a vessel in which the circulatio takes place(circular distillation).

(J. B. Porta : De distillatione, lib. ix, pg. 39, Rome 1608)

• The Pelican in the old "Scottish Rite", a symbol of the old eighteenth or Rose Croix Degree of the Ancient and Accepted Scottish Rite
• Masionic view of the Pelican
• Some deeper aspects of Masonic Symbolysm -  by Arthur Edward Waite -  PDF