These guys brought the garden party with them. Apparently, they don't like to bathe alone. As soon as one or two landed to take a dunk in the fountain, the rest of the flock followed.
I had to take my pictures from inside the house in this case and, even then, they flew away as soon as I got too close to the window. But, as soon as I moved away, back they came.
My mother-in-law identified them for me: they're Cedar Waxwings.