I hadn't checked on the Bell's in a while so I wandered by this morning.
It's still singing away. It sounded a little quieter to me, not sure if that was real, or if it's starting to lose some of its interest. The rate of songs sounded unchanged to me.
It's already molting as evidenced by the swallow-tail. It's surprising to me that it's still singing and trying to attract a mate while its feathers prep for migration, but then again if anything will sing till the end it'd be a vireo.
And proof that the summer if flying by, we've moved right past clubtail season (July) and into the Darners...