A.P.
I think that the bullying behavior is more of a power thing right now than a mean-spirited thing. Remember, negative attention is better than no attention. Also, kids are so egocentric, that they have a hard time realizing that their actions affect other people. They have some videos at the library that demonstrate what bullying is and give role-play scenarios and then ask questions about the scene, like "How do you think that made "victim" feel when "bully" laughed at her like that?" and "How would you feel if someone hurt you like "bully" hurt victim?" etc. Basically, I am suggesting a mini-sensitivity training course in 5 year old language. Also, I don't think that consequences such as time-out or taking things away help him to see why his behavior was unacceptable. Try to focus on the behavior and not the child as you don't want him to get a negative self-image that only fuels the behavior. One thing that worked with one of my students was to have him be our "feelings" person for the day. At various moments during different activities, I'd stop the class and ask him how so-and-so must have felt (about getting an answer right, or sharing, or having someone help her with something such as carrying a toy for her, etc). It really helped him realize that people are people and have feelings just like he did. The kids really liked it too (they're all 3 and 4 mind you), so we do this from time to time now as a game.