Well, that's something new....

There's a hole in the ice on the pond, with a plume of 'steam' coming out of it.  It looks like a hot spring that's mostly frozen over.  What it really is is a spot near the heater where the water has some vertical turbulence off the rill.....  The rill itself has a skin of ice over almost all the rapids -- the flat rock at the top where the water comes out and the pool about halfway down are still clear of ice, which is enough for the birds to use.

It's warmed up to 15F in the sun.  That's warm enough to go run errands. (yay?)  If the sun stays out, i expect that some of the ice on the rill will melt, which will be more useful for the birds.