what does "shot birds at" mean?

"The months visiting my mother in the hospital never left me. The nights I spent laying awake in her room, looking, thinking, feeling. Watching as the nurses checked medication and vitals. Listening to the whirring of the IV drips, their alarms BB-RRRing-ing in the night. Smelling the tube feeding liquid, a milk-looking substance with a scent all its own.
And it ain't like pot roast.
Dad visited three or four times a day. He endured the brunt of Mom’s frustration and confusion. Her fear. At one juncture, Mom just shot birds at Dad, who had shown nothing but absolute care for her. She would not even watch TV."

In the last paragraph, what does "shot birds at" mean? Laugh at?