Monster in a Cage

Ever since Isabella died, Ferdinand has been acting like a "monster" in a cage. His cage is on the opposite wall from Buddy's cage, and they can see each other. Ferdinand acts like he wants to get out so bad and rip Buddy to pieces. I put a towel up on one part of the cage so Ferdinand can't see Buddy. But he goes to the part that I can't cover with anything and watches Buddy. He stares at him, lunges towards him, shakes his head at him, etc. He even jumps up and rams his head at the door as if he's trying to open it. Good thing the door is just hardware cloth or he might really hurt himself. I put bricks on the corners to hold the door down because it has no latch.
Buddy most sits up at the top of his cage looking down at Ferdinand like he's saying, "Yeah, you wanna piece of me? I can take you!" He shakes his head and puts out his dewlap. Sometimes he crawls up and down the front of his cage. Actually he crawls up the front then dives back down to the bottom with a big thump sound when he hits the bottom. Then he crawls back up again. He does this a few times before he perches for his staring contest.
Well, maybe things will calm down after a while. I don't know if Ferdinand is just really missing Isabella or maybe he thinks that Buddy stole her away. Who knows?!