Curious Question

[Rememberthedeer]

I'm just going to tell you right off the bat that this is nothing important, but I'm just curious about something.
Today when I went out to go feed my rabbits I went over to my buck's cage. (He's a 4-5 year old flemish giant) and as soon as he saw me coming he started to pick up the straw in the cage with his mouth and hopped back and fourth along the wall that I stood closest to stopping and stare at me every time he reached one end of the cage. He was constantly letting out this weird humming sound (it kinda sounded like an insect). He would pick up straw and put it closer to me then go grab more straw and continued this routine hopping along the wall, humming like a bug. I've never seen him act like this before and am wondering if something was bothering him. His ears and tale were both perked up so he didn't really look afraid, his eyes weren't big or anything. As soon as I left he stopped (I could hear him from a distance and when I backed away out of his sight the hopping and humming stopped) but when I came back into view he started up again. He has NEVER done anything like this before... What's he doing? Is he trying to tell me something or is he just being silly?

 

[Rememberthedeer]

Like I said, it's not really important, but for anybody out there whose just as curious as I am, here are a few things that I THINK might have triggered his sudden behavior.
1. I just moved his cage. I'm not sure if this has anything to do with it but he used to be place right next to my does. One of them (right next to where he used to be) is currently nursing a new litter of kits, while the other (right across from where he used to be) is currently pregnant. Over the winter his cage kinda fell into a mini sink hole so I had to move it (I'll have to move the nursing doe's cage too, but I'm going to wait till her kits grow up a bit). Since he's no longer in view of his little "harem" would that have anything to do with his behavior? Is he lonely?

2. He is the father of both litters (currently here and to come) so maybe he's twitterpainted or something.

These are the only reasons I can think of (other than he's just having a little fun) does anybody else have any ideas?