The Physiologus says of the eagle that when it grows old, its eyes weaken and its wings become heavy. To renew itself, the eagle finds a spring, then flies up into the atmosphere of the sun, where his old wings and dim eyes are burned away. Descending to the water, the eagle bathes three times and its youth is restored. The interpretation says that when our spiritual clothing and sight grow old with sin, we must fly up to the "sun of justice" (Christ) which will burn off our sin; baptism then renews our spiritual vigor.
The Epiphanius version says that the eagle is the king of birds, and lives for a long time, up to 100 years. When it grows old its eyes cloud so that it cannot see, and its beak grows long and curved so that it cannot eat. The old flies high in the air, then dives down to break off its beak on a cliff. It dips itself in cold water and looks at the sun, and the cloudiness of its eyes falls away. The interpretation says that the multitude of our sins oppresses us, but through the water of the tears of repentance we will be renewed.
The van der Borcht copperplate engraving below combines two attributes of the eagle in one image. A cheerful sun (with ears and hair!) has already burned away the eagle's old feathers, and the eagle is diving toward the water. It is also breaking off its too-long beak on the cliff.
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In the woodcut below (from the Rome, 1577 edition) the eagle is near water, but is only breaking its beak on the rock. The sun seems unhappy or angry.
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Properties of the Stag 
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