I found an excellent article about bullying in Kindergarten. While there is not as much research on children in Kindergarten as there is on children in upper grades, it seems that the evidence suggests there an equal amount of bullying in both situations.
Children in the younger grades may not receive the same attention for their actions because teachers and parents may have trouble believing in aggression or meanness at such a young age.
According to Bullying in Kindergarten, at education.com children are not necessarily mean. They do, somehow, benefit from their actions when bullying. The article give powerful examples of exclusionary behavior, name calling, throwing stones, damaging schoolwork, and actual physical aggression towards other students. The children are apparently aware that the behavior is unacceptable and should learn positive ways to adhere to social standards.
It is no surprise that the children who are targets are often very nice children who are generous toward their peers. They also have a hard time making friends or asking to join the group. These children can be helped with their confidence levels and learn positive ways of asserting their desire for respect. These children are often called passive victims because they do not actively respond to the abuse.
There are also aggressive victims. These children are usually not adept at self-control and their behavior is used by the bullies in a hurtful manner. They are not as adept at making friends and respond aggressively in social situations.
Within the peer groups there are other children who inadvertently or intentionally participate in the victimization of other children.
Children who assist the bullies do not initiate the abuse, nor they participate all of the time, but they to participate in the victimization from time to time.
There are other children who do not participate in bullying at all. They are bothered by it and will occasionally stand up to the bullies for their peers. According to the article these children are not usually victimized in retaliation. I think that is especially important. As a parent I would find it hard to encourage my child to stand up to a bully for their peers if I believed they would be victimized themselves.
More on the effects later. In the mean time, do you recognize a child as fitting into one of these categories?
Source Bullying in Kindergarten- by Francoise Alsaker