What caused the strange doppler-radar images captured in these photos?

[Dayle Record]

I have seen flights of starlings that are huge, and as they lift they form the half-to full curve feature, as a part of lift off. Once I was in a parking lot in the mid Salt Lake Valley. I looked up to the mountains in the East. Suddenly and I mean suddenly, three huge forms appeared out of thin air. There were two large black circles and in the middle was a form like a circle with a couple of arms out of the bottom. These forms were at least two miles large stretching about 6 miles wide. They were out in front of Mt Olympus to the east of the city. In the next second they had disappeared again. I stood there and they reappeared, then disappeared. I called out to a woman nearby, and asked if she wanted to see something extraordinary. She stopped for a minute and when they reappeared, she cried out. I told her that my best guess was that they were flights of starlings, and they were turning in unison, so that when they went on edge they disappeared. We watched them for a few turns more. Their regularity was startling, and that very "startling" quality might be where their name "starling" comes from. Innocuous as it may sound, that stands as the most engaging natural phenomenon I have ever witnessed.