The image is actually one of the Pelican. Elizabeth Braidwood on her website says this of the pelican.
The pelican of the Middle Ages was thought to pierce herself in her breast in order to feed her blood to her young. Alternate stories tell of how the pelican would kill her young in a fit of pique, and then pierce her breast in later remorse. The blood thus brought forth, falling on the dead chicks, brought them back to life.
Generally, depictions of the pelican are meant to indicate Christ the Saviour who shed his blood in a like manner.
In medieval heraldry, a pelican is an eagle-beaked bird always shown plucking at her breast. If shown alone she is blazoned (described in heraldic terms) as "vulning herself". If the young are shown with the parent, she is blazoned as "a pelican in her piety".
The Physiologus, a second century work of a popular theological type, described animals both real and imaginary and gave each an allegorical interpretation. It told of the pelican drawing the blood from its own breast to feed its young. The physical reality which probably resulted in this legend is that the long beak of the pelican has a sack or pouch which serves as a container for the small fish that it feeds its young. In the process of feeding them, the bird presses the sack back against its neck in such a way that it seems to open its breast with its bill. The reddish tinge of its breast plumage and the redness of the tip of its beak prompted the legend that it actually drew blood from its own breast.
The Physiologus, and later Latin Bestiaries of the Middle Ages, found the action of the pelican, so interpreted, as a particularly appropriate symbol of the sacrifice of Christ the Redeemer shedding His blood, and thus the symbol of the pelican grew to have a wide usage in Christian literature and art. Thomas Aquinas did indeed use the figure of the pelican in his beautiful hymn appointed to be sung in Thanksgiving after Communion, the Adoro Te Devote:
"Pie Pellicane, Jesu Domine,We also find a reference in Dante's Paradiso (25.113), and in Act IV, scene V of Shakespeare's Hamlet, Laertes says to the King:
Me immundum munda Tuo sanguine. (verse 3)
O Loving Pelican, O Jesu Lord,
Unclean am I but cleanse me in Thy blood."
"To his good friends thus wide I'll open my arms;In medieval and baroque art, the pelican is often found as an ornament on altars, chalices, and tabernacle doors.
And like the life-rendering pelican,
Repast them with my blood."