What's Everyone Yelling About? Cedar Waxwings at the MJC West Campus

Cedar Waxwings (Bombycilla cedrorum) always strike me as quiet unassuming birds. I've had flocks of dozens in my flowering pear tree that were so quiet that I almost missed them entirely (it doesn't help that their call is so high-pitched that I can't hear them).

I was wandering around the northwest corner of the west campus of Modesto Junior College yesterday, near the "mini-wilderness" of the sheep pasture. There's a watering tank that birds often utilize, and yesterday was no exception. There were several dozen Cedar Waxwings flitting about in the trees, and eight or nine at a time were getting water. I snapped a few pictures from a distance and didn't notice until later that they looked as if they were yelling at each other.

What was that all about?