Hunting red deer in their roar (rut)is great fun. If you can get high on a ridge line and let out a good roar you often get a great response.
There's been times when I've had deer roaring back at me from two ridges across.
Sometimes you get one silently sneak in to check you out, other times it's like you have a fire breathing dragon on a string and all you have to do is keep playing the tune till he's standing on top of you.

Sika are even more fun, they'll fight anything so a halfway decent imitation of their squeal/roar can get them in fight mode instantly. They'll often charge straight in on you.

the biggest mistakes people make is:
1/ Over doing it, don't go roaring every two minutes. Best thing to do is go listen to a few stags on a farm to see how they do it.
2/ Don't try to sound like the biggest baddest deer ever bred. In a life and death fight would you rather fight a heavy weight boxer or some weedy nerd? Most sane people would choose the nerd, deer aren't stupid.

The original international turd