My mealy worms had been disappearing without me being able to see who's eating them. I had a few days off from work and I was finally able to see what was happening.
The orioles seem to be the ones really taking advantage of the worms. The female lands, eats a couple, grabs as many as her beck can hold, and then takes off.
One night a bluebird was taking a long look at the mealy worms, but then the oriole flew in and grabbed the last one. I put out more mealy worms and the bluebird returned.
First he took a long luxurious bath in the bird bath and then he flew over and ate a worm. A course my camera wasn't nearby so I wasn't able to get a shot.