Where does “ulucus” come from?

ulucus (Latin) comes from Latin ulula, from Proto-Indo-European up- — to call, to cry, to yell.

Ancestry of “ulucus”, step by step

Step	Language	Word	Meaning
1	Latin	ulula	screech owl (Tyto alba), tawny owl (Strix aluco)
2	Proto-Indo-European	up-	to call, to cry, to yell