I do not mean while we're riding (she never tosses her head then) but rather when she's loose in the pasture. It is definitely a horse-language thing and I want to figure it out. I have noticed several variations of this movement but it always involves flicking the head in some manner. All of the horses seem to do it, and when my horse tosses her head to another horse they respond, so I know that it is used for communication.
My Monty Roberts book briefly mentions that a head toss can mean "I didn't mean to do that" but I cannot imagine that all of the horses I see would be saying that all the time!
I am really curious about this now. I want to know what my horse is trying to tell me when she does this. Does anyone have any clue as to what it means? Or if you don't, could you tell me in what situations you have seen your horse toss his/her head? I've got to get to the bottom of this!
(I'm sure that after watching them in the pasture for long enough I will be able to figure it out, but I thought this might help to speed up the process by giving me something to look for)
Here is a (very dusty and old) picture for reference. Sorry it's so big, I made it smaller but it sill displays in the same size.