Yeah it could be a nesting thing I guess! Not really sure, but it's quite sweet watching him be desperate to get a bit of hay over to her and her totally ignoring him! He did it a few times last night, a couple of times it looked like she was trying to get it ('kissing' through the bars) and he dropped it - felt so sorry for him!
Once they are both neutered and 'safe' are they going to be housed as Mr & Mrs? She might change temperement once she's neutered. And it will be interesting to see how they interact when they are together.