Parashat Balaq indirectly references "Tzippor" five times (by introducing Balaq as "ben Tzippor"). I don't believe Rashi brings down any background regarding Tzippor. If the Torah refers to Balaq as "ben Tzippor" so often, who was this mysterious figure?
The Zohar HaQadosh (3:184) writes:
[Balaq was called] "son of Tzippor" as was already stated; but, [he was] truly a son of birds for his sorcery was conducted with a few species of the same bird!