Defend Ability?

Anyone know how you can write a trigger to detect when a unit activates/deactivates defend?

Ive tried "unit begins casting abil" Abil=defend" etc

any ideas?

Dunno, try to check the current speed for example. I used this in one of my systems. However there were no slow spells.

nah, the "defend" ability im referring to is just a "duff" ability that fires triggers when its activated/deactivated. Activing the "defend" alone does nothing. I just needed an ability you can turn off & on that has infinate duration.