Adding a small mirror to the chain of a rotisserie motor deer deterrent is a good way to increase visibility.

I salvaged this one from a tool I had that was used for viewing hard to reach spots on a copier.

At first I left the mirror dangling, but after a few days of observation decided it would be better for it to be secured to the chain.

The two copper cups also give off a reflection depending on where the sun is and how much movement is happening.

It might also be worth pointing a light at the deterrent when the sun goes down if you experience any night nibbling.

The rotisserie motor deer deterrent fits nicely onto a 1x6 piece of treated lumber. This was done by drilling 4 holes in the back of the plastic cover on each corner where the motor is mounted. Secure it to the 1x6 with small wood screws and put the metal cover back on.

I used some scrap roofing shingle material on the top to increase protection from foul weather. A piece of metal or plastic would do the same job. I always seem to use whatever is in the barn when a project like this is unfolding.

Just before sunrise or after sunset is sometimes when your garden is most vulnerable to marauding deer.

I've recently been exploring night time illumination techniques in an effort to increase the deterrent factor a few degrees when the sun is sleeping.

These electroluminescent night lights are cool to the touch and only use a few pennies of juice per year.

Stay tuned for more details on a few different applications I'm trying with this electroluminescent technology.

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.