After watching Daniel Pyron demonstrate the "defend" command with his 11-year-old mixed-breed, Amanda, I was inspired to try teaching the command to Dori, my Kuvasz.
We live intown and, whenever there is a big sporting event at the dome or stadium, advertising blimps (Goodyear, Fuji, Budweiser, SeaWorld, Family Channel) pass over our house. For some reason, Dori goes nuts whenever a blimp is near. She hears the distinctive low rumble of the motor and begins barking hysterically while searching the skies.
When she spots the gas-filled nemesis, she runs along the perimeter of the yard, barking to ward it off.
I suppose this is instinctive guarding behavior - protecting our property
from the slow moving blimp is similar to guarding the sheep flock from a
hovering vulture or a skulking wolf. Of course, the blimp always moves
on, reinforcing Dori's notion that her efforts were responsible for driving
away the enemy.
Whenever a blimp comes by, I shout "defend!" Over
time, Dori has come to respond to "defend!" by
looking up into the skies and barking, whether or not a
blimp threatens us.
A dog doesn't have to dislike blimps in order to learn the "defend" command. Anything that the dog barks at would work just as well for training.