I would say moles or voles are your culprit. We had similar tunnels in our yard near our raised bed veggie garden. A patio is an unusual place for them to be tunneling, but not unheard of.

We certainly have moles (and voles) in our yard, and we have a meadow abutting the lower part of the yard (and it's FULL of voles every summer, which I know because they all run into the barn when the guy cuts the meadow in the fall!) But I agree... why are they bothering with excavating the patio when they have all that lawn, meadow, etc. I don't see tunneling mounds in the gardens beds around the patio so I don't think they are simply passing across the patio to get to them. So it just makes no sense to me?? (But I'm not a mole... :)

I agree with nancylouise, moles or voles. Yesterday I sat and watched a little vole run and scamper between a clump of Iris and a clump of ornamental grass in my garden. I thought it a bit nervy of him but no damage that I have noticed. Our patio is brick with no space between the pavers that would allow them to dig. Looks like your little critter is engineering a few scout tunnels. Good luck.

sooey

Voles and moles make these little mounds to aerate their tunnels. We run over them every week with the lawnmowers and flatten them, then the mounds pop up again in both new and old locations. Trickier when the air mounds are between bricks or stones. Cement perhaps?

I wondered if there is something, like ammonia or vinegar, that I could pour over the cracks to discourage this activity?? Cement is not really an option given the ways the stones settle and shift. I was hoping having stone dust between the stones would discourage anyone from digging up through it (kind of sharp little bits of stone) but apparently not... :(

Ammonia sounds cruel; vinegar, I don't know if that would be a deterrent.

I doubt that moving all those stones is a plan you would willingly embrace, but moving the stones closer together so that there is no space between them might prevent the problem, as it has for mcsooey.

When I built my little patio garden, I dug out the area, then put down roofing paper/tar paper, then sand, and then the patio bricks, touching each other, no visible spaces between them. It didn't prevent weeds, as organic material settled into the narrow cracks between the bricks and became home to some weeds, but no vole mounds have ever showed up there. I guess it depends on how much of an annoyance the vole/mole excavations are vs how much effort it would take to get rid of them. Good luck.

(I think if that nice patio were mine, I would just stomp the vole mounds and sweep away the excess dirt every day or so, rather than tackle a work-heavy permanent remedy, but then I'm a lazy gardener, so take my words with a grain of salt!)

That's what I've done so far... tamp down, fill, repeat. I keep thinking they will get discouraged and move on! The patio was here when we bought the house (so I have no idea how it was built) and if we ever have the whole thing lifted and reset, we would certainly reduce the space between the stones. But we aren't going to do that until we have to for other reasons, like significant settling. The weeds are what has driven me nuts -- I've tried to encourage GOOD plant material such as moss or a low, groundcover thyme (that would smell nice when walked on) but haven't had much luck getting them to take. Crabgrass, garlic chive and fennel volunteers from the nearby herb garden ... no problem growing between the cracks. I have moss galore in my yard but when I've tried to "seed" the patio with it, my tunneling friends just uproot it and I get messy piles of moss and dirt. I do wonder if I were to just let dense mats of weeds take over and just weedwhack them to keep them low, if that would discourage the tunnels... be tougher to work your way through? I don't honestly know...

My 'go-to' remedy for so many problems critter/bug related in the garden is a good sprinkling of diatomaceous earth. If you can find the tunnel opening or ending, sprinkle some about. Moles, voles and mice will avoid it. If what you have are air tunnels, it might not help at all. But if these are exploratory tunnels, whatever it is that is making them will go someplace else. I love diatomaceous earth and use it for everything from ants to slugs to mice. If you get it at a local nursery it can be pricey but at Tractor Supply you can find it in big bags and, can afford to keep a good supply on hand. This may be of no help at all; just giving you something else to think about.

Good thought!! I actually have some already -- bought it for the cutworms we had (for the first time) with our tomatoes this year. We do have LOTS of holes in the garden beds, which are either entry or exit holes. I'm resigned to these guys in the lawn but think they can darn well stay there and out of my gardens and patio. I think our Agway sells it in larger bags, too, so I will check them out.

You all make me so thankful for a sweet (almost comatose on your lap) cat and shepherd mix, both of whom display their talents. I wonder about our song bird population, but they've never brought me a bird. Voles? Got a couple last week!

My two rescue cats are pretty good mousers BUT... they are indoor cats, because we live right next to 133 acres of private land that is chock full of everything from coyote packs to red fox and black bear (latter has been a frequent visitor the last few years!) So they don't go out and are limited to catching the field mice that make it into the basement. (From there, they are usually transported, totally unharmed in most cases, to our master bedroom... ;)

Yes! Rescue cats, of course! They rescue the poor sick field mice in the dark, scary basement and take them to the Sick Bay in your bedroom for recuperation. And all this time I thought "rescue cat" meant something else. ;-) right back at you!

In NH we had a bear coming right up to the front porches of houses on our mountain. Really surprised me that he felt that comfortable. I know you read about it in the news, but it was still weird to have it happen right at our place. The closest he got to our house (I think) was the compost pile, which was several yards away. Deee-licious, I'm sure. The free-range chickens loved the compost but he never visited unless we were gone or it was night, which meant the chickens were safe in their coop.

We did lose a special cat, so you are wise to keep them indoors, especially since there are so many mice that need rescuing.

So ask him why he can't lounge around the patio when the voles are there and make himself useful. He's gorgeous! Maybe he's just eye candy, like so many other people in this world.

I hope you get to post a new photo like that in our "Birds and other mobile creatures" posts. That would be great!

Honestly, it is amazing how close he is, and how perfectly he posed with the rudbeckia behind him.

Brilliant! A guard bear. He would be more effective than my golden retriever, who has so far slept ... in a chair just inside the patio door... soundly through every one of his visits. She barks like mad when the UPS guy goes up the street in his truck, but not a peep for a large black bear parked a few feet outside the door. Go figure.

Yep. And that's the patio of bluestone/mole/vole fame. He's ambling around from the iris patch where he took out the first hummingbird feeder in this shot (I'm inside the house with a zoom lens... but still). This shot is just before he sat down and sent that baleful gaze my way. (Amazing how much they resemble Steiff stuffed bears!) ;) And that's garden path that leads from the patio around to the butterfly garden behind the house (bear prefers to use the path too). What's amazing is how agile he is ... hardly breaks a stem even when he takes a shortcut through the beds. I take the air horn every time I go out to weed these days!! :)

In NH this season there was a big hullabaloo about some bears that had become too acclimatized to people and were visiting unsecured dumpsters, trash cans, and bird feeders in the Hanover area. Due to the governor's intervention, they were relocated, rather than killed, but generally bears just return to their previous haunts, so I don't have confidence in their long term survival. I don't have those things out that will attract bears since while I love the bears, I don't want them to view my house as a food source, and I would rather that they remain safely wild and afraid of people.

I agree that the tunnels are moles, voles, or perhaps chipmunks, and based on my experience I would do whatever is needed to discourage them. Our brick patio literally has spots where the tunneling is so bad that bricks have dropped down into holes. It needs buried wire mesh around the margins and then to be rebuilt entirely.

Home Depot sells castor oil in yellow bottles in their garden section as a pet- and people- and groundwater-safe mole repellent. Mix with water and carefully pour between all the cracks so as to not leave a residue on the stone. Then pour a band around the outside of the patio at least a foot wide to discourage them from coming to the area. If moles, the worms may be finding cool, damp spots under the stone and the moles are following the food. If chipmunks, it's a predator safe zone due to the stone roof for them. Voles just are always tunneling looking for food!

I asked my stone savant who did my work. I think he's amazingly talented, and has both technical skill and artistic ability. He said, "It looks like the stones were set in an unusually thick layer of sand or stone dust and a mole was tunneling under there. "

By the way, he did this for the Boston flower show. No mortar, all completely friction held by careful stone selection.

If anybody in the Portland/Midcoast area of Maine need stonework done, contact Matt Carter at Green Island Stoneworks. He's crazy talented and knows how to make a solid, stand-for-a-few-centuries wall.

A definitive ruling from an expert (what GORGEOUS work!) ... moles it is. I have no idea how the stones were set as the patio was here when we bought the house. We add stone dust every year or two because if I pull weeds (manually) from between the stones (which have fairly wide separation in some cases), all the existing soil and stone dust comes with them and I end up with a trench. So I sweep new stone dust over the top with a broom in hopes it will keep the weeds (dandelions, garlic chives, and fennel seedlings from the herb garden are especially hard to remove) at bay. But as to how much is underneath the entire patio -- no idea. I am curious now as to how the moles decide where to raise the roof (so to speak) ... it's different places different days. Are they just experimenting? Or are they after something in particular? Some days it's on one side of the patio, other days, the entirely opposite end! We do have worms galore throughout the beds and yard -- so many and so fat and big I actually called our agricultural experiment station to find out if we had too many. They ooze up in the garden beds whenever I stick a trowel in the ground, like a sci-fi movie! So if moles like worms... we've got a bumper crop under that patio, I'm sure! Many thanks for the consult! :)

Moles *love* worms. Worms are their primary food source. In fact worms provide both food and water for moles. You can't have too many worms, but you can have too many moles, or at least mole mounds in the wrong places!

Well, that explains the moles! When I talked to the "worm expert" at our Ag Station a couple of years ago, he told me it was impossible to have too many worms (however, I am not certain that these are not "Crazy Snakeworms" in which case... I think you can?!) Some parts of my beds are more castings than soil! They are even living in the gravel path... When I asked how to reduce the number so I don't have to garden in boots to avoid having them swarm over my feet (yuck), the scientist asked "do you add compost?" and of course, being a gardener, I do. I topdress with compost every year. So he suggested I stop that for a few years, and the numbers will dwindle a bit. I somehow always thought of moles eating grubs, not worms. But the last year or two, our lawn feels more like walking on a soft sponge... at least I know we don't need to aerate the turf :(

Oh moles will happily eat grubs too! I saw a documentary nature show about moles, and wish I could find it again now online to post for you, but my search turned up nothing. It was very interesting, and sort of funny in parts when it spotlighted the continual battle of wits between Mrs Mole and the Lawnmower Man.

I have both moles and voles, brought home to me on a regular basis by my cats (RIP). The voles are the reason I can't have crocuses or tulips. Voles love the bulbs like moles love earthworms. So anyway, I'm very familiar with the squishy feel of earth beneath my feet in spring. It's a whole other world in the subterranean depths!

It sounds like the moles have not put even a dent in your earthworm population, anymore than the army of tirelessly hunting felines here has ever inflicted on the mole and vole populations.

Love that photo of the close up of the bear with the Fennel and the Rudbeckia? Great shot!

Helps to have a powerful zoom lens at such times! :)