Here's why:
* Hieratic Dragon Nuit's effect: It states "When this card is Normal Summoned or Special Summoned:" This means the effect only triggers when it is summoned using either of those methods.
* Tribute Summoning: Tribute summoning involves sending a monster(s) from your hand or field to the graveyard as a cost to summon another monster. This is not considered a Normal or Special Summon.
Therefore, while Hieratic Dragon Nuit might be sent to the graveyard by a tribute summon, its effect will not activate.