What is she saying? Her rapid wing fluttering seems to have some other message than just stretching the wings. It’s a tense sort of flutter, sometimes with the wings held halfway closed. She also vocalizes briefly during the exercise, although her tweet is drowned out by the nearby males. I’m reading the standard writeup on these birds (Birds of the World by the Cornell Bird Laboratory) and the authors mention a rapid fluttering of the wings done by males as a prelude to copulation, but there’s no mention of rapid wing fluttering by females. Their prelude to copulation is to get down low and hold wings tight. So this behavior is one more entry on my long MATWOB list (Mysterious Are The Ways Of Birds).
A nearby male appeared to pay no attention to the female’s display and looked at me with what I took to be an unfriendly expression. If it were much larger or I smaller, I would have left the scene without delay.