Is it legal to put a wireless security camera inside my residential mailbox?

I have a custom mailbox at the end of my driveway. It looks nice, but the mail carrier doesn’t always put the flag down, and we don’t always put it up.

I’ve also noticed on our driveway camera that, on at least one occasion, a car drove up and stole our mail shortly after it was delivered.

I want to install a small wireless camera in my mailbox (like a Blink camera) to notify me when I have mail and hopefully deter mail theft. Is this legal? Some websites suggest it’s not, but the laws seem vague and mostly mention not tampering with mailboxes if they are the property of USPS.

I understand there are specific laws in the United States regarding mailboxes. This is not a ‘Property of the United States Postal Service’ box, and it’s not a public mailbox. It is only used for our house.