Egg #7 and interesting behaviour

This morning (before 5:45am) we got egg number 7

Later in the morning I observed some interesting behavior: the female sits on the nest, spreads her wings and opens her beak like she is screaming, but no sound comes out. It appears to be some display towards the male who is nearby (probably in the entrance of the box). You can hear HIM calling.

Interesting behaviour, 3 May 2012 6:45am

I have seen similar kind of behaviour before from the female, but I have no clue what it means…