They don't have something like a house where they can stay warm through cold nights?That's interesting. They tend to quack MORE when the patio light is on. There is still another patio light on the other side of the yard, but they do NOT like it when we don't turn it off (or so it seams).
They are in a closed run with access to underneath the chicken coop, but fully enclosed. They prefer to just sleep out in the run though, and never go underneath.
Oops! - You're in SoCal, never mind!
My ducks have a cozy house with straw on the floor, nesting boxes and plexiglass windows to look outside, but since i have added a run to the house most of them prefer to stay outside overnight. Except for when the weather is really bad, like horizontal rain for example.