There are birds and coyotes in that area that make noises frequently.
Don't know if anyone has mentioned this but I was running around the buildings at the sandy shore hangar and kept hearing what sounded like a baby Dino or or weird bird I've never heard before. Are there vultures in the game? I haven't seen any. It's probly nothing but there ya go
With that being said this isn't a regular bird call like you usually hear. It's weird lol. Also when you walk out of the sandy shore clinic there is a rock formation that almost looks like it has an egg on top (you find a space ship part there). I got to the top and you have a perfect view of chilliad and there is a road going straight tords the mountain (kinda reminded me of the straight line on the mural) also I noticed contrails in the sky that make a big x over what I think is the wind farm area. Gonna go check it out