Mystery bird

At least I think it's a bird. In the middle of the night I hear an eep, eep, eep... for pretty long periods of time, with breaks now and then. It could almost pass for some kind of alarm sound. It's not incredibly loud, though not seems to be in an otherwise quiet forest.
What is it?

That's not a lot to go on, but the "Eep Eep" sound is a dead giveaway. It's a Giant Blood Thirsty Red Breasted Zombie Alarm bird. These are common to Northern California forests that had weapons grade Plutonium dumped into the trout streams near old military bases.

The "Eep Eep" is actually a means to track warm blooded prey. Normally, during daylight hours they will follow the trail of Snicker Bar wrappers and dropped Trail Mix to find you, after dark they rely on the hypersonic resonance generated by the "Eep Eep" beacon to illuminate your hind quarters, so they can drop you before you have a chance to scream and flee.

Bear Spray isn't effective, you'll need at least a 6" Smith in .44 caliber ...

Although DWH’s answer is more likely here is another possibility
https://www.mercurynews.com/2013/09/10/morris-what-the-eep-is-that-bird-doing/

Suggest you locate the owl and attempt breast feeding.

Atleast it’s not a peacock...

might not be a bird.....Chupacabra

Haha, that's funny!  Nice try but pretty much everyone knows chupacabra don't do their Eeek call until mating season after the summer solstice

Even though I still don't know what it is, the replies have been worth the post!

Sound like this Juan?

Suggest you locate the owl and attempt breast feeding.

Best advice on here so far!   

Hey Bird! That's not it. It's not a screechy sound. More like a constant beep, beep, beep...

Hey Bird! That's not it. It's not a screechy sound. More like a constant beep, beep, beep...

   

Maybe a cassowary? One of my friends was attacked by one and nearly died from being disemboweled.

Hey Juan - OK, sounds like it might be a northern saw-whet owl.  They have a regular spaced beep that can go on and on and on at night.  Also possible to be a northern pygmy owl but they often call at dusk and usually don't go on and on in the middle of the night like a saw-whet.  Other small owl out there would be western screech but there call is not the regular spaced note. Have fun!

Probably a great horned owl. Google their sounds, play a few because different ages and sexes make different noises.

My guess would be northern saw whet owl. We get them here on rare occasions.

coincidentally we just heard a northern screech owl here a few nights back. The name is misleading because they don't really screech at all.