“Idmon, Phoebus' son,… to him the Father gave by his ordinance the foreknowledge of omens divine, whether he inquired of flames or close-viewed entrails smooth, or of the air thick with fowls that cannot lie.”
Phoebeius Idmon, ...
cui genitor tribuit monitu praenoscere divum
omina, seu flammas seu lubrica comminus exta
seu plenum certis interroget aera pinnis.
Source: Argonautica, Book I, Lines 228 and 231–233