Weird noise up by battery??

[izackary]

So last night I heard a strange noise when I started up the car. In fact I thought it was an animal in the woods! It was like a cross between a whippoorwill cooing and a coyote yip. It has happened every time I have started the car ever since. In fact it is a little intermittent at first but it settles down and goes away. I haven't been able to localize the noise yet other than it is in the area between the driver side headlight and around the battery, maybe near where there looks to be a manifold, possibly for the air ride lines.

I am puzzled. Any ideas??