^Yeah, I know she is shovn during the credits, but at the time you bring her into the temple, Link knows that Hyrule is bound to drown, but still has no second thoughts of leaving her several stories below the ocean floor. Even though she managed to get out, it was quite unexpected. Not only that, you let the innocent girl witness the massacre of the hundreds of temple guards on your way down there. And it's clearly established that the room she's left to pray in has no source of water, food or a proper sanitary system. Not to mention ventilation, heating or any other feature a room needs to keep a bird girl alive.
(She's also too weak to open the heavy stone doors out of there, you notice when you guide her that she can't leave the room on her own).
Link's a sadist.