I've noticed lately that the Grackles have been taking their food to the fountain to wash it or soak it before eating it. Especially now with the fledglings follow the parents, they are learning this activity as well. It's usually the whole or chipped peanuts they prefer to do this with. The suet, they just gobble up. After some research, it looks like this is a pretty common activity.
I guess with some foods they've learned that it softens them while others, like peanuts and hard seed, don't respond this way but a habit is a habit. It was fun watching the parent hop across showing the fledgling how to treat the food this way. Which also explains why there's been so many peanuts and such at the bottom of the fountain basin!