Trigger With the Tongue

A 7 a.m. drive in the country didn't produce much (2 deer and 5 sand-hill cranes), but I can generally count on seeing 3 horses and a donkey at this place. 

So, why did Trigger get the blip over the other 3 animals? It's the tongue of course. You show me tongue...it's almost automatic.

Through the road mud,
and through the horse dung.
I crept up to the fence...
to shoot the horse tongue.