[21twelve]

” .... but now I can see that there is a distinct tri-lobed pattern in the tail that may be caused by the flapping of wings ...”

I thought of birds getting into bioluminescent stuff - but that is usually salt-water, although I did see an article on some rare freshwater stuff. (Google Earth shows the American River nearby - a google search of that mainly brought up e-Coli!!) Anyway - with the bio-luminescence - birds could dive in, get covered with the stuff, and then it wears out or the algae or whatever dies in the air).

Also something called a “click beetle” that has it, along with some other insects.

[Swordmaker]

I thought of birds getting into bioluminescent stuff - but that is usually salt-water, although I did see an article on some rare freshwater stuff. (Google Earth shows the American River nearby - a google search of that mainly brought up e-Coli!!) Anyway - with the bio-luminescence - birds could dive in, get covered with the stuff, and then it wears out or the algae or whatever dies in the air).

That's one thought. . . but how is it turned on and off?

Also something called a “click beetle” that has it, along with some other insects.

That's a good possibility. I'm going to contact the County department of Agriculture and pick their brains on luminescent bugs. There does seem to be a native firefly in California. . . but I've never seen fireflies come down from so high in the sky, or occupy trees so tall.