I have mockingbirds around at night but they don't screech.
I have another songbird also but don't know what it is but its not screechy either.
Is it just at dusk or really at night when very dark?

I guess I should have said I live coastal San Diego. They are not mocking birds. They come well after dark They fly about 50 ft off of the ground. I also believe they had a nest in a tall palm tree. I thought they might be barn owls, but the sound they make doesn't match what I researched.

Bats? We have bats around here. Their wings flutter very rapidly. No screeching though.

Owls here hoot back and forth to each other, after dark for several hours and again just before dawn.

Maybe they are barn owl fledglings??? Here in Temecula we have barn owls and hear a lot of screeching at night when the young ones are being taught how to fly/hunt. Try the Raptor Forum - they are very helpful.

Barn owls screech. I'll bet it's baby barn owls.
Renee

How about Screech Owls? We have those here in the Fresno area.... why not SD

LOL, Renee!

Yep, barn owls screech, go figure! You're lucky to have those guys around eating up your rodents and gophers.

tim45z10,
I'm pretty confident that you're seeing one of these: http://en.wikipedia.org/wiki/File:Tyto_alba_1_Luc_Viatour.jpg
It's a Western Barn Owl (which are apparently found all over the world). We've have some nesting in a neighbor's palm tree two years running. They're beautiful to watch... powerful fliers. They frequently swoop in low to investigate my nieghbor when he leaves for work at 2:15 a.m. Noisy with an oddball collection of vocalizations. Sometimes they make a sound like a squirrel-cage fan motor that's out of balance (chikchikchikchikchikchik...) for minutes on end. Enjoy, they're big rat eliminators.

Here is a link that might be useful: {{gwi:561850}}

I've also heard them make sounds like tires screeching on pavement and a tick tocking noise.

If it's an odd noise at night, it's prolly a barn owl. :)