On my way home from work, I noticed the front passenger side is squeaking. It sounds like a bird chirping, which is the best way I can describe it. It only makes that sound when it compresses. I can replicate the sound by pressing hard on the shock tower.

The suspension is fairly new, Tokico D-Spec's with FRPP N-Springs. I put those on mid-May 2013, so I doubt it has to be changed already. I don't have a sway bar, so it's not that.

Any thoughts on what it could be? Anything I can check that will help with a diagnosis?