I think she is suffering from empty nest syndrome. We haven't seen the kitties in over a week now. Last we saw them, Mama was teaching them how to hunt. It is my guess that the window of opportunity has ended for trapping them, unless someone else has.
Mama has been coming around to eat, waiting patiently by the back door for something to nibble. She hangs out on our back wall. Is she waiting for the big gray cat to return? Maybe we will fatten her up enough to sustain another litter this season.