You definitely don't need the clicker! Any noise or cue that the horse can perceive and you can repeat will do. I use a kiss noise because I kept dropping and losing my clicker-esp when riding.
And for those who think that we shouldn't treat our horses like dogs (why not?) clicker training was actually developed by people who train killer whales and dolphins. Elephants in Nepal are now being trained with it instead of being tied up and beaten into submission. If you can use it to gain control of a three tonne elephant what is wrong with using it to gain control of a 1000 pound horse.
The most dangerous horses I have ever encountered have all been trained (very badly) with negative refinforcement. Very few horses learn to buck, rear, bolt or shy because they got carrots at the wrong time, but plenty of horses learn to do all these things because of negative reinforcement gone wrong. This forum is full of stories about such horses.
Horses are blameless participants in training- its up to us to get it right
Last edited by corymbia; 08-12-2012 at 07:56 PM.