I'm showing my city slicker background but here goes anyway...
I moved into the country about 2 years ago and I have all manner of wild critters roaming the place. Armadillos, opossums by the dozens, coyotes, bobcats, deer, egrets and herons, hawks and vultures, you name it and it's out here. At night, in the wooded areas and high grass, there is this sound. It's kind of a staccato "eh eh aw, eh eh aw" and it's somewhat rhythmic with a pretty good echo to it. When my dog goes out she stares off into the dark looking toward the sound and she obviously sees (and smells) something but I can't. She's not afraid of them as opposed to those times when she snorts and raises her hackles and won't get off the deck. Whatever it is, it's year 'round and there are a lot of them. It sounds like they're all talking to one another. Any ideas on which critter it is?
I'm not a good sound interpreter, but is there any chance that you could have owls around?
There are several good websites with recordings of the calls of all kinds of birds - I bet you could go to one of them (I think Cornell University has a large collection) and listen to a few of the different owls that might be local to LA to see if any match up.
I have owls but I know an owl when I hear them. These critters are on the ground whatever they are. I'm pretty sure it's not a bird. I'm wondering about the opossums or armadillos. I'm going to see if I can find something about what sounds they make. It's a really weird sound.
Look for (or more appropriately listen to) fox sounds. Our dogs know they're out there but are calm and accepting of their presence. Here are some calls. Listen to a variety because some are like barking dogs and some are bird-like. http://www.angelfire.com/ar2/thefoxden/sounds.html
We have several large owls that reside too. They make interesting noises but not near the ground. This is all in the middle of the city, BTW. We and many surrounding neighbors have left our properties undeveloped thus creating a wildlife habitat.
Those were fascinating fox sounds. Some of them are a lot like a bluejay. I don't think that's what I'm hearing at night; although, the one called "foxweird" is pretty similar so I'm not completely ruling them out. The only foxes I've seen out here unfortunately have been those hit by cars. Same with the skunks.
I'm familiar with raccoon noises, it's not them.
I found opossum and armadillo sounds online and neither of them sounds right. I never really thought about deer because it sounds so close to the ground but they make some pretty odd noises and they're everywhere in threes and fours. It's driving me crazy not knowing what they are.