Ds has started biting older children at nursery -sometimes provoked but often not. To put this in context he has just a)realised his dad goes away sometimes and noticeably misses him b) moved up a class at nursery and c) his little sister is now moving and sitting up (she is 8 months). I've tried time out and so have the nursery but it doesn't appear to be working. I get the impression that nursery are finding him really hard work at the moment. He seems to go up to children who have a toy he wants and just bite them. His language is good for his age and I'm sure he could ask for help if he wanted to. Any suggestions as to how to deal with this?