When I was a kid my best friend had a collie named Rex. Rex was our constant companion on all activities from biking and playing sports to hunting and fishing - he just tagged along. All summer long he would hang out by our sides or rest in the shade while we played. Pick up a gun in the autumn and he turned into a bird dog. Coursing in front of us and flushing birds and marking where they fell when we shot them. Put the guns away, and Rex would not even look at a pheasant - smart dog.