I had forgotten about another friend who had a pair of GSPs back on Whidbey Island in the 90's. Very nice dogs, and he hunted with them. A bunch of us (all in the same squadron) also had dogs, and mountain bikes, and we'd take our assorted pack with us camping, hiking, and cycling.
One day, during a hike, my friend ended up having to learn how to rappell in fairly short order. One of his GSPs saw a bird, and jumped for it, and disappeared as it cleared the shrub the bird had been in.
Neither dog nor owner had realized a bluff backed onto the trail just past that bush...
Luckily, no injury to the dog - except perhaps for its pride. It came to rest about 15-20' below the trail, on a small ledge. My friend, and a couple other guys, managed to rig a harness which my friend took down to the dog (via the aforementioned rappelling), then the other guys helped haul dog and owner back up to the trail.
I don't believe that dog ever made another blind leap after that one.
Edit: My friend and his wife used a book called Gun Dog to learn training techniques for their GSPs. Both swore by the book.