UgashikBob,
I have noticed the same thing before the rut with the moose. They seem to be totally unpredictable and unresponsive to any calls that i have made. Later in the rut and during rut though, they seem to key in on the sounds and respond to them. You're absolutely right about them treating it as a "non event" before the rut. I figure before rut, they don't need to respond to anything basically because they have no need to fight for anything. But once the cows start giving the scent and the bulls are busy trying to round up the females, they then see it fit to respond to calls and investigate things. I don't think it takes too much in terms of "exact sound" once rut is going to perk the bulls. The natives have used birch bark callers for a long time with success and today many people still do the same thing with success. I do know though that pre-rut, those moose will sure respond quick to a wolf howl. Basically, it's the "Get Outta Town" call and sends them packing.
-Snowcamoman
