Boss has a habit of tracking everybody at my workplace - suspect he's listening in on phone calls

So, we were all given work phones and laptops for the job that I do currently. He stated on day 1 that he could track our locations with the phone - which I was a little iffy on at first but due the nature of our work, I guess it could pass as an "okay safety feature". Thing is, the guy monitors it A LOT. On top of this (we weren't informed), he very regularly looks at our emails - stuff in our inboxes, stuff we've sent, etc. We found this out when he made a remark about another employee emailing her mom about something - it more less slipped out.

Now, I have a good feeling he's listening to calls we make on our work phones, whether as they're happening or recorded and listened to later. We make quite a few calls, and occasionally to other coworkers. I won't lie the odd time we've vented to each other (we have an interesting job to say the least and its good to get a lot of it off our chest just to help process what happened). The odd thing is, shortly after, its not uncommon for our boss to bring up in a meeting or directly to us in person something that has to do with what one of us has spoken about over the phone. The timing seems incredibly coincidental and although it isn't 100% to do with what was being said, it's starting to make me paranoid.

Can calls be recorded in this way for my work to listen to them after the fact? Is this even legal?