This is what we saw:
their talons would come out...
The next day they were at it again, this time over Beaver Creek (probably because it was very very windy at Pilar).
I've read about this as part of a mating ritual. But these guys were juveniles; they hardly had any white to their necks yet. And they did not grab on and hold to each other as they freely fell, as the Internet says is the ritual for courting.
What's also interesting, is that an adult would be close by and occasionally fly with them. When she'd leave, the young ones would do their hit-and-fall routine over again.
I think it was a training lesson, being monitored by the parent.
That's my story, and I'm sticking to it!
PS What you see in the background are islands in the bay as the birds fly 1,500 feet high, along the top of Pilar Mt, from where we watched, during our picnic lunch.
The small fleck you see in the second picture is a commercial fishing boat, way down below.
Pretty cool, we thought.