The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
"Like to a bull," etc.-- This is another story told by the Master in the same place and about the same people. The circumstances are the sane as before.
Once upon a time, when Brahmadatta was king of Benares, the Bodhisatta became the spirit of a castor-oil-tree which stood in the approach to a certain village. An old ox died in a certain village; and they dragged the carcase out and threw it down in the grove of these trees by the village gate. A Jackal came and began to eat its flesh. Then came a Crow, and perched upon the tree. When she saw the Jackal, she cast about whether by flattery she could not get some of this carcase to eat. And so she repeated the first stanza:
On hearing this the Jackal repeated the second:
The Tree-spirit, on seeing this, repeated the third:
"The lowest of all beasts the Jackal is,
The Crow is lowest of all birds y-wis,
The Castor-oil of trees the lowest tree:
And now these lowest things are here all three!"
 When the Master had ended this discourse he identified the Birth: "At that time Devadatta was the Jackal, Kokālika was the Crow, but the Tree-spirit was I myself.
300:1 Folk-Lore Journal, 3. 363. Compare No. 294.