Chirping sound

I have a 2008 Mariner that has just started making a fairly loud chirping noise from the from. It is not always there, sometimes when the car starts it doesn’t always start for a minute or two. Any ideas what it means? Thanks!

Is the chirping there while you are driving, when idling and not moving, or both?

Both

I am going to assume that “a fairly loud chirping noise from the from” means that the noise is coming from the front of the car. Ideally, you should really localize it for us as to whether the noise is coming from under the hood, or whether it seems to be coming from another area in the front.

However, I am going to take a WAG and speculate that you have either one of these two situations:
A serpentine belt that is loose/glazed/worn.
or
A failing bearing in either the belt tensioner or an idler pulley for the belt.

Both of these situations are more likely to reveal themselves when the engine is cold.
I suggest that you leave the car at your mechanic overnight so that he can listen to it when it is first started the next day. Bear in mind that either of these possibilities can wind up stranding you when the belt snaps.