As I approached, the shadow of a Dragon flying above me, blocked the sunlight. While he was flying over me, he disabled all the Shriekers with a single spell... They fell to the ground, disabled.
Long story short: if you cock-up, do the dragon's quest and you'll be fine.
Good tip. That one actually caught me completely by surprise: I'd just helped the dragon and was on my way to deal with the shriekers and had a moment of "I've no idea what just happened". Very handy, though.
