We've been lucky with most of our deer deterrent installations by having tree stumps and fence posts to hang our clanging contraptions from.

There was one place in the garden we needed protection but had no tree or stump to use.

That's when a metal fence post comes in handy. Just stick it in the ground enough for it to be stable and you've got yourself a platform that is affordable and portable.

Being able to move your contraption around provides flexibility, which is helpful when the enemy forces you to change your tactics on a moment's notice.

I've found after several generations of these mechanical deer deterrents that sometimes a smaller sound can have more of an impact than a more steady, louder crash.

I'm pretty sure deer have excellent hearing, which should mean they would be alarmed at any unnatural sound. I've even noticed how the sound of a chain saw doesn't seem to push their alarm buttons.

This set up allows for several variations which helps to prevent a situation where the enemy might become accustomed to the deterrent.

Stay tuned for more details on a low budget delay circuit. I'm still working out the details, but ideally it will have an adjustment knob where the delay interval can be set to a wide variety of choices.

My family is afflicted with a hereditary plague of groundhogs.  It all started with my grandmother, who let the groundhog in her backyard thrive, despite nibbles in her garden.  More recently, my mother told me the tale of the groundhog in her own Virginia backyard.  (Just so you know, Tobin is her dog, and Maggie and Joey are my siblings.)

Joey has had groundhog battles of his own.  His small vegetable garden was the full-time buffet for another groundhog, which came out at intervals to munch on pea shoots and anything else young and tender.  Unlike the female side of my family, though, Joey won the battle with his groundhog.  He baited a live trap near the garden, and waited.  The groundhog must have been laughing up its figurative sleeve since it just went right on eating out of the garden, ignoring the trap.  But one day...

Luckily, my own groundhog travails have been limited.  Following the maternal side of my family's karma, I bought a property chock full of groundhog holes --- you could barely walk through the soon-to-be-garden area with twisting an ankle.  But I also acquired a handy, dog-loving husband.  When the groundhogs met Mark's deer deterrents and Chesapeake Bay retriever, they split for parts unknown.  Maybe I've broken the familial curse?

I estimate the zone of protection these mechanical deer deterrents provide is around 50 feet.

If you've got a big area to protect you'll need to install multiple units. I discovered last year that it helps to vary the noise signatures so each deterrent has its own unique chime.

At our most vulnerable spot I adjusted the design a bit to allow for a double bang. This is easily done by having something hang in the spot where the clanger rebounds to after its first hit.

After a few weeks of adjusting you'll begin to learn how to listen for each sound. This is important because you need to keep an eye on how they keep operating. We had a power failure back in the winter and it didn't take the enemy long to figure out our defenses were down.

We're always looking for innovative ways to keep deer out of the garden, so I thought I'd share this example from the blogosphere.  Freshman Farmer writes:

That does sound like quite a simple solution, although I'm sticking to Mark's deer deterrent since it is proven in our high deer pressure area.  If anyone else has tried out fishing line, though, I'd like to hear about your results!

Dave left a comment a couple of weeks ago linking to Transport Canada's Deer Exclusion Devices and Deterrent Techniques.  While we were researching our own deterrent, I read a similar document put out by a U.S. state (can't remember which one) noting the best way to keep deer off airport runways.  It sounds like airports are working hard to find a way to deter deer!

I've excerpted a few of Transport Canada's key findings about deer deterrents since they match our experience:

"The key to success when using frightening methods and repellents is to use them at the first sign of a deer problem."  This has been our experience as well.  Once deer find that tasty strawberry plant, it's going to take a lot more than a gentle clanging to chase them away.  But if you deter the deer before they find your garden's tasty crops, they will keep out.

"The general obstacle to the use of sound for effective animal control is habituation.  Many animals adapt to new sounds and learn to ignore them if they are not associated with real danger....  Shooting has been used to frighten or kill deer in agricultural fields.... In these situations, deer are often killed to reinforce the effectiveness of non-lethal deer scaring devices."  I have to admit that I back up our deer deterrents with a bit of hunting, and I think it helps.

"Gas cannons can be more effective at dispersing deer if the frequency of the explosions is varied and if the cannons are moved every second or third day of use to a different area....  Motion-activated exploders, triggered by passing deer were more effective than exploders that fired at regular intervals.  Thus, the exploders only fired when a deer was close by, which made habituation less likely."  We're not using cannons (boy was someone desperate!), but Mark is working on making our deer deterrents less regular to get the same effect.

Transport Canada notes that ultrasonic noise, reflecting surfaces, and blinking lights don't work.  That's been our experience as well.  They note that odor and taste-based repellents "are only even partially effective at protecting very small areas."

Stay tuned for more gems from Transport Canada later in the week!

Transport Canada didn't focus on deer deterrents as a way to keep deer out of airports.  Instead, they concluded "In most cases, the use of deer deterrent techniques should be used only to provide temporary control until a more permanent solution, such as fencing, removal or killing, can be found."  So far (knock on wood), we've found our deterrents to be a permanent solution.  But we're just now reaching the end of our first twelve months.  So, in case Mark's clangers fail, here are Transport Canada's top recommendations for more permanent control:

• Habitat modification can be used to reduce an area's attractiveness to deer.  "Typical actions include the pruning or removal of trees and shrubs; and the removal of standing water (ponds, ditches, puddles), alteration of grass heights, selection of broad-leaved herbaceous plants (forbs) for planting, and paving. The main goal is to reduce the airport property's attractiveness to wildlife."  This is probably a good idea at an airport, but clearly isn't going to cut it here on the homestead where we're actively working to encourage most wildlife.
  
• Fencing is Transport Canada's primary recommendation for a permanent solution.  They recommend that deer fences be 10 feet tall and consist of galvanized steel chain-link or high-tensile fixed-knot.  On the other hand, they note that electric fences "are effective in excluding deer under favourable conditions, but they will be penetrated when deer are motivated to cross them, when short-circuited by tall plant growth, or if snow accumulations exceed the height of the lower electric lines."  I don't doubt that a ten foot tall chain-link fence would keep the deer out, although I do doubt that I could ever afford to fence in our two acre garden and orchard to this level.
  

The entire article is interesting reading, and I recommend you start from the beginning and browse the whole thing.  Thanks again for sharing, Dave!

The clanger on the right was my first attempt at attaching a golf ball to some sort of connector.

One big problem is the pointed end and how it tends to get hung up if the opportunity presents itself.

That's what got me using these eye bolts which is the clanger on the left. Well worth the additional funds to streamline this vital aspect of the back yard deer deterrent.

Grandpa Brock built a deer deterrent that works on exactly the same principle as ours --- many thanks to his grandson for pointing me in the direction of the embedded youtube video.  If you watch through to the end, you'll notice that Grandpa Brock adds a pebble to the can to mix up the sound a bit.  We're coming to realize that minor adjustments like this are enough to keep the deer on their toes and out of the garden.