losing troops upon starting a fight

[Ish]

My situation is as follows:

I am in the elf lands with an army consisting of demons, scoffer imps, demonesses, imps, and dyrads.

Before each fight the amount of dryads I have reduces by about 50.

e.g. when walking around the map I have 699, start a fight and I have about 640... and they are gone forever.

I am playing on impossible if this makes any difference.


Has it got anything to do with morale?

Cheers.