Sometimes it's a case of dogs doing what dogs do. I hunted an old dairy farm property a while back. They had dogs, horses, bulls etc. A dog treat every time I showed up & they quickly learned the sound of MY truck & became happy to see me. Guessing you take the garbage out & check the mailbox fairly often??? A box of dog biscuits won't break the bank & the dog may become a security asset for you. I've seen a bunch of mail persons handing out treats. AS ALWAYS if your life is truly in danger, do what you must.