Spaniel buries retrieves

My cocker has taken to running off with his retrieve and burying it. Why does he do this?

Graham says: Some dogs do. It is a throwback to when they buried “lunch” to make a cache for when the pack fell on hard times. Unfortunately, this trait seems to be inherent in some of the working cocker lines. Go back to basics and start doing your retrieves with your dog on a two-metre lead so he has to go out and straight back again. Give him lots of calm praise for a good delivery. Work on your recall and practise getting him to walk to heel carrying the dummy so that the retrieve stops being such a big deal.