Vole damage

We've got a real problem with voles. A few years ago, when I had just planted my first trees, they girdled many of my trees. When I saw what was going on, I circled each tree with a few feet of mesh metal hardware cloth. It seemed to do the trick. Despite having plenty of voles around, none of my trees were girdled - until this year... Under cover of snow, they girdled many trees (15-25 trees probably won't make it). They burrowed into my hardware cloth barriers from underneath-- I guess that's no surprise, but why did it take them 3 years to figure out ? I will continue to use the hardware cloth on all trees, and I've just started to mulch with pea gravel, hoping that will fill their burrows as fast as they can dig, as well as suppress competing plants. I'd like to embrace the forest edge ethos but now I'm afraid to not mow the heck out of my orchard for fear of giving these suckers a nice habitat. I have 3 cats, and they each do their share of vole killing, but it doesn't seem to dent the population. I'd like to encourage more predatory birds and even coyotes, since they would help, but I'm skeptical that the problem would go away.

I'm ashamed to say that I put poison in their burrows for fear of losing all of my trees and it seems to be working. I don't feel good about using poison (it must be an excruciating end), but would love to have any others weigh in on it. For our trees (and us) to live and thrive, some organisms (deer?, voles?, lepidoptera?, bacteria?) have to die, right ? But where do we draw that line ? And if it has to be done, what is the right way to kill ?

Any vole advice is welcome...

Josh Klatt
Ohio River Valley
Zone 6b

kestrel nest boxes recommended. they eat many voles a day. Boxes are simple to build, a basic bird house, but google it for design, put on fence posts extensions.

Old 99 farm
dundas 5b ON

The following are possibilities not experience:
1 I just recently read that voles really prefer to feed on grass not bark; if true, keeping areas at base of tree clear of grass may help. I used vacuum picked up leaves (1/2 rotted and matting)as mulch for years to control weed growth under and around trees and had minimal vole damage, but many of these trees were mature trees & not really so susceptible. Had little damage on new trees; all were in areas mowed like rough lawn.
2 Many years ago I heard a strategy( from Penn State?) but I never used or saw it put to use. Surround orchard with a band of crownvetch (3 feet wide?) , clear inner area of voles, keep area mowed, and more will not migrate in across vetch band.
3 Put your gravel down at the base of new trees when planting before backfilling all soil, imbed screen tube in gravel, use at least 1/2 bushel per tree.
4 Deter them with Plant Skydd ( a Swedish forestry developed mammal repellent, for deer, rabbits, voles etc. ), expensive, OMRI listed, long lasting, blood meal with a vegetable oil sticker.
5 "Poison them", with a vitamin D based poison which makes them accumulate toxic levels of calcium; but does not affect any animal predating them. I found it recently available again from Brandt Consolidated who now owns Monterey Chemical; the supplier. May also be on the VA supplier list (from the resources page of this website).
6 Encourage foxes: Anyone know how to do this? If you need to have deer fencing; how to let the foxes pass in and out?

Hope these ideas are helpful.
Dan Lefever
SE Penna
zone 7a

Part of the solution in my opinion is reducing numbers of any pest to tolerable numbers. Although I protect all the orchard trees here with wire mesh screens, it is impossible to wrap the many thousands of nursery trees. For the last few years I have bees simply setting out grosses (yes, actual grosses) of old fashioned spring traps for mice and voles. I am now getting almost no damage on the trees. Formerly we would lose hundreds (and I mean foot long sections of trunk turned to dust, not mere girdling). Peanut butter is the choice bait. I put them in coffee cans and milk cartons, and reset often. I normally catch in the hundreds. Since I am now experimenting with zone mulching (think heaps of debris) I will be trapping heavily in these piles, as that is indeed where they will be resting, and where they will find their final resting place...(diabolical laugh here).

Walden Heights Nursery & Orchard
Zone 3 in Vermont