Ruggie says he has excellent hearing and there have been a few examples of this, such as how he can identify the denomination of coins by sound alone, and he is the first to react to the sound of the floor opening up during the firelotus drama of Glorious Masquerade.
Ruggie also credits having good ears with helping him pick out uncertain customers while he is working at the school store and says both he and Leona have “preternatural sense of hearing” as they eavesdrop on a conversation in the botanical gardens, but Leona might actually have the better hearing of the two of them.
We see Ruggie get surprised by Silver once and by Leona twice, while Leona is able to sense an eavesdropping Jack in Book 2 but Ruggie is not.
Jack says Ruggie “supposed to have some of the best eyesight out of anyone in Savanaclaw,” and Rook suggests that Ruggie’s spelldrive talents are aided by his “keen eyes.”
Twisted Wonderland Reference Note 