‘Candida avis’ is usually assumed to be the white stork (Ciconia ciconia). T. E. Page, the Loeb editors and others give a footnote to this effect. T. F. Royds in The Beasts, Birds and Bees of Virgil (Oxford, 1914) says of ‘Candida avis’:

‘This is by common consent ‘Ciconia alba’, the white stork. It is a migrant in Mediterranean countries…a most useful bird feeding chiefly on snakes and other reptiles’

He then cites Pliny (N.H. 10.31) and Juvenal (14.74–5) ‘serpente ciconia pullos nutrit’ to confirm the snake-eating propensities of the stork.

Virgil's ornithological mystery is not, however, quite so easily resolved. There is another contender for ‘Candida avis’, one more convincing both on a textual and an ornithological basis — Circaetus gallicus, the short-toed eagle.

The short-toed eagle is the only European snake eagle, its diet being almost exclusively snakes. Lizards, and much less frequently small mammals or birds, may also be taken.