I have a 3 year old Jack Russell who is a complete darling. Loves children/people/other dogs etc. I have one problem with him. When he is off the lead in our communial garden if someone he does not know walks accross the grass he will run up to them barking and circling them with his hackles up. This is terrifying to the person he is doing it to and embarrising for me. Granted they should not be there as they do not live there and he only does this to adults never children - the opposite he runs up to them wagging his tail and licks them. What is going through his mind and what is the best way to cure this. It is only in our garden never in the park and never when he is on the lead.