Skip the gun and install an alarm system. If you know little about guns, there’s a better than even chance something will go very wrong if you actually find yourself against a burglar.
And I’m with others who think it’s just probably some dumb teenage prank.
Teenage daughter with teenage boys across the street. Hm.
And the gloves were tied to the trees–like fingers wrapped around a branch and knotted? Double-knotted?
I don’t know, if I was a robber or a serial killer I don’t think I’d leave warning clues.
Dog poop: That sort of thing really gets some people irritated–especially if they are very into their lawns. Pee is even worse. Might be something there because in my experience dog-haters can be very irrational.
Get those action detection lights and an even bigger dog. 
Return the gun. Have a chat with the parents of the boys, whose kids would, of course, never do such a thing, and mention how terrified your wife was.
I lean toward the kids,
FWIW,
No idea if it is a prank, or something more sinister, but I think if oyu are a bit nervous about guns you probably shouldn’t get a gun.
How about mace/pepper spray? If you accidentally plink a kid it isn’t lethal and you can teach the teen to use it. [and get a taser for the adults?]
And get liberal cell phones with orders to shut themselves into a reasonably secure room and dial 911 immediately until you can get an alarm system put in.
See hilight below. Did I miss something?
Another thought–“waist high.” Was the 5yo simply playing? Had she been to the doc’s?
LOL! If you find a jar of vaseline next to the trees run!!!
I also don’t understand why you would call 911 for something like this. It’s a very weird thing to find on your property but I don’t think you are in danger.
I thought rubber gloves came from trees.
Do not obtain a firearm. You ain’t ready.
Since I can’t rule out that this is burglary-related, I have to figure that’s the worst-case scenario. I highly doubt that it’s burglary-related, but it’s just so bizarre that nothing I come up with makes any sense. One thing I suppose I haven’t made very clear because it’s hard to describe–in order for this to have happened, the perpetrator had to have walked onto our property–30 feet down the driveway, then to the first two trees in question (next to where our driveway meets our garage), then continue alongside our house on a pathway between the house and the row of pine trees, through a gate (no lock, just a latch), down a small slope where the pathway dumps out into our backyard and the row of pine trees ends (right at the back edge of our house, where my daughter’s bedroom is), and tied the last glove to that last tree in the row which stands maybe 10 feet laterally from the back of the house and from my daughter’s bedroom. In other words, the gloves could not have been placed where they were by approaching the trees from the public strip outside the fenceline.
Gloves were chest-high (on an adult), as written in the OP. If I wrote something else later, I was in a hurry and not thinking.
I’m in the military and have zero compunction about killing. I do have concerns about my kids, so maybe the pepper-spray is a better route.
Oh yeah–no, it could not have been the 5-yo. We don’t have rubber gloves anywhere, she hadn’t been to the doc’s, and she wouldn’t have been able to place them–she’s not a tree-climber and doesn’t spend time outdoors near those trees. And yes, the gloves were tied by the fingers. I think two were single-knotted and one was double-knotted. Not sure if this has any meaning.
At least with the vaseline I could put two and two together and it’d make some sort of sense and I could lean heavily toward prank. And the 911 issue is answered in post #18.
Bird shot in the shotgun is a option. Typically its non-lethal and will deter anyone you hit. There’s always a small chance a pellet might hit an artery but birdshot is certainly less lethal than buckshot.
I’m thinking a dogwalker wanted to stash their poop pickup gloves. Maybe putting them on a tree to get and use another day? Not sure why they came so far onto your property.
When I was a teenager, we found some still-good lettuce in a dumpster out behind a grocery store. For whatever reason, we decided to take an ungodly amount to do who knows what with. On the drive home with our treasure, we noticed several cars with their windows down. Inspiration struck and we decided to start putting it in any vehicle left in this fashion. Some were way up far along winding driveways. We had to go pretty far on their property to do so. Why? I have no idea, but at the time, I thought it was the height of hilarity. And yes, I’m ashamed now. 
So, I’m guessing kids with pranking on the mind. Just like in our case, that was our only transgression. I’d be surprised if you ever had any further problems.
I agree that it just doesn’t sound like burglar activity. They have addresses, you know? Why would you use bizarre signals rather than saying “Hey, let’s go rob 123 Apple Road.”
In any case, anyone could be casing your house at any time. Your family is no more danger now than they were last week or last year. Professional robbers are not going to want to do anything when people are in the house, anyway. It just puts them in danger. Only junkies and other desperate people rob a house that is obviously occupied, and those aren’t the people who are going to plan something in advance.
This may be a good time to review if your house is as secure as you’d like it to be- trim bushes, install motion-triggered lights, make sure your locks are sturdy, etc. But I wouldn’t freak out. It looks like a teenagers screwing around to me (teens think rubber gloves are hilarious, because they are kind of like condoms.) Is it possible that teens might take a shortcut through your yard? In my younger days, I’d sometimes hop a fence to cut a few minutes off my walk to school.
(Would type something witty but I’m still laughing too hard.)
Maybe its some kind of hobo code.
… not really.
Either a weirdo prank, or someone in the neighborhood has come to the conclusion that the only thing that repels invasions from Saturn is a deep-seated alien fear of latex.
Regards,
Shodan
I don’t know why it was done, but I know what I’m doing with any leftover rubber gloves now.
Moderator Warning
Dufus, you’ve been around long enough to know political potshots are not allowed in GQ. This is an official warning. Do not do this again.
Colibri
General Questions Moderator
According to TV cop shows, crooks always leave their fingerprints on the inside of rubber/surgical gloves. But if those you found were brand now, I got nothin.
Since this requires speculation, it is better suited to IMHO than General Questions.
Colibri
General Questions Moderator