We've worked up a multi-prong approach to keeping deer out of our garden.  First, dot the edges with homemade deer deterrents as the main line of defense, but keep your eyes open.  If you see a deer too close, take a potshot over its head and then add another deterrent in that spot.

This fall, I've added a third leg to the anti-deer campaign --- cover crops.  Fall and early winter are the worst times for deer damage in the garden since food sources in the woods largely disappear after the last acorn is consumed.  And while a summer deer visit just means that a leaf here and there is nipped, the smaller and slower growing winter garden can be completely defoliated in one night of deer gorging.  Cover crops give you a bit more wiggle room, since they are succulent and tasty at this time of year, so they attract the deer's attention before the beasts devour your beloved strawberry plants.  I noticed that during our two small deer incursions this fall, the plants that got eaten most were oats around the garden edges, which left me smiling instead of swearing.

Mark has really kept on top of the deer deterrents this summer, and we haven't had a single incursion in months.  In past years, deer damage was already starting to get extreme by late October, but it's possible that wild foods are especially abundant this year, keeping the deer well fed in the woods and out of the garden.  As always, it's a lot easier to figure out why the deer got into the garden than to try to decipher which factors are keeping them out, but I can't help pondering the issue.

Of all the natural foods, acorns are perhaps the most important in a deer's fall diet.  Since oak trees mast --- produce few nuts most years, then all gang up and produce a bumper crop during certain years --- it's unsurprising that studies have shown varying percentages of acorns in a deer's diet.  A quick search of the web turns up figures ranging from 20% to 75% for acorns' contribution to the diet of a white-tailed deer.

Not all acorns are created equal, though.  Oaks can be divided into two large groups: the white oaks, including white oak, chestnut oak, and others with rounded lobes on their leaves; and the red oaks, including red oak, black oak, scarlet oak, and others with pointy lobes on their leaves. 

Although you might have a hard time identifying the acorn you find on the forest floor, a deer is much more discerning.  Acorns in the white oak group are sweet, with low concentrations of bitter tannins, so they are a preferred food early in the fall.  As you can see from this photo, though, white oak acorns make up for their tastiness by sprouting quickly, so by late October, there are often few unsprouted white oak acorns around for deer to chomp on.

That's when red oak acorns shine.  With their bitter nuts, red oaks figure they can wait until spring to sprout, and the tannins do deter many seed predators.  But by late fall, deer are getting hungry, so they turn to the red oak acorns.

Since red and white oaks tend to produce bumper crops during different years, deer often end up hungry during either the early fall or late fall, but in our neck of the woods, both red and white oak acorns are currently common on the ground.  Clearly, this double mast year has kept the deer very well fed.

I learned from reading Jim Arnosky's excellent juvenile book "All About Deer" a key element that must be fully understood by the back yard deer deterrent maker.

"A deer can swivel each of its ears around on its head to listen in two different directions at once."

This fact indicates that even the smallest garden could benefit by deploying at least two deterrents at each end of the protected area.

In my opinion the sound puts a deer in caution mode, but it's the movement that usually provokes bolting.

While our garden is 80% better protected than last year, I have to admit that our foes got in a couple of times this month and nibbled on some beans, sweet potatoes, and strawberries.  Looking back over my notes, I noticed that the deer chomped on our garden at the exact same time last year.  I think the deer life cycle must involve shifting feeding strategies in mid summer as the wild foods lose their spring luster (especially when drought slows down growth in the woods.)  Now is the time to be hyper vigilant and stop deer damage before it starts.

On the other hand, I think at least half of this year's deer damage could have been prevented.  After seeing no deer activity at all for months, we got a bit lax and let some of our deer deterrents stop working for a few weeks.  Bad idea!  Mark's currently inventing a more dependable deterrent that won't get hung up or burn out its motor at inopportune moments to prevent this problem in the future.  Meanwhile, we're keeping an eye out for signs of deer so that we'll know when to upgrade our defenses.  It also seems to have helped to mow down a huge weedy patch at the edge of the garden where the deer could find cover.

In December, our power went out for two weeks and we stole all of our deer deterrents' extension cords to hook the fridge and freezer up to the generator.  After the power came back on, we let our deer deterrents slide.  After all, the deer were following their winter paths, a good distance from our garden, and all of our succulent perennials were under a thick mulch cover.

Recently, though, I've been seeing hoof prints a bit too close for comfort.  Tender shoots are beginning to pop up both in the woods and the garden, and I suspect the deer's gut bacteria are making their shift as well.  I figure it's only a matter of a few days until they discover that my strawberries are sending up new leaves, and then we'll be done for.

So I sent Mark out this week to plug the deterrents back in.  It took him an hour or two to get them all running, disentangling wind-blown chains and rewiring bits that had pulled loose.  Now I'm regaled by the gentle clang of deterrents as I work in the garden, and am content that my fruits and vegetables are safe for the moment.

One of the reasons our deer deterrent works so well is because of the movement of the golf ball.  I was reminded of this when a deer walked quite close to me in the woods the other day.  I had stopped to rest, so the deer had a hard time deciding whether my still form was just another stump in the forest or was something to be afraid of.  It watched and waited, stamping its hoof to try to startle me into motion, then decided I wasn't a threat and wandered on its way.

The most effective deer deterrents always seem to include some kind of motion.  I encourage you to keep this in mind when designing your own!