This is way to adorable! Barking at sprinklers and at a cat. I love it.
Mine bark at each other sometimes or if I take in a foster glider

. I think they like to tell the newbie who is boss even if they are not in the same room.
My Morticia barks randomly if she decided she didn't get enough meal worms or meat and will just stare you down and bark non-stop until you give her some. (This is at all hours of the night.)