I also have a 14 SGS and at times hear a similar sound and mine is coming from the push button on the gas lid cover. While I was riding one day and heard noise I held down on the button slightly and it disappeared. Haven't tried to resolve yet.
Mine came loose and was rattling pretty good. Had the dealer replace it for me, and then that night I taped the flap up to its roof. I never close the thing anyway.
I have a 14 SGS and it has the same chirping noise coming from the front end. I don't think it is the vent. I did solve another chirping noise that was caused by the provided tool kit it the saddlebag. Two of the wrenches were rubbing together because the vibration ripped the tool case apart. Fixed that.
Some people report that a failing wheel bearing can chirp. I personally have never found this to be the case...usually it's a rumbling noise. But I'm just passing it along.
Seeing that y'all have had a nasty winter, which means you can't ride as much as you wish...look for signs of a bird nest with baby birds....I hear they chirp a lot.