Pets

He will stick his paw in the water like he is trying to catch whatever is causing all that activity, and feel around for it like it was prey -- of course, he splashes water out when he does this, so when he withdraws his paw the bowl is lower and is automatically refilled from the reservoir, with accompanying gurgles and bubbles, setting off a new round of excitement ... he used to do this for several minutes at a time, but seems to have tired of it as he's gotten older.

When he was still a feral kitten, I had the water bowl on the back patio and he would clamber all over the reservoir when he was trying to catch whatever was making the bubbles -- even knocked it over once. I wrapped a towel around the reservoir so the bubbles couldn't be seen and he didn't do that afterwards. Maybe that's something to try, and it's easy to do.