Budgie Breeding Question?

Question
Hi Leah! Today the female budgie visited the nest box a lot. She sat in there and the male budgie came outside and sat on the perch. It looked like he was feeding the female. The female also is more aggressive now. Can you tell me what's good and what's bad? Is it possible they mated while I was at school?

Answer
They've probably already mated and the female will probably have eggs soon.  It is common for the male to feed his mate, especially once she starts to incubate the eggs.  Aggression is pretty normal; she's just protecting herself and her future babies.