After midnight I was outside and heard a flock of birds approaching. Big birds. I'm not sure what kind, but their calls were loud and frequent. I don't think they were geese. I know they weren't ducks. They may have been some type of swan. They flew overhead, quite low, making quite a ruckus. It was like a big avian party flying over my house. I couldn't actually see them, but I certainly heard them as they flapped their way toward Paradise Lake. I'll have to see if I can find out what kind of large birds winter in the Sacramento Valley. I'd like to get a look at them in the daylight, sometime.