If deer pressure is high, chemical repellents may not be enough. Mechanical deterrents can be used in combination with liquid repellents or used alone. There are several products recommended for deer control that don't fall under the category of either repellents, or fencing.
Wireless Deer Fence™ -
Each unit has a scent reservoir with a perfumed oil that is attractive to deer. When deer investigate, they receive a small electric shock. The deer learn to avoid them, so you'll need to keep moving the units, but they're easy to move. Powered by two AA batteries, the shock is humane but strong enough to startle the hungry deer.
The Havahart® Electronic Repellent for Deer
uses a technology that attracts deer to posts with a lure scent. Then repels deer from your yard or garden with an slight electronic shock less than a static shock might be. It is extremely similar to Wireless Deer Fence. There are pro's and con's to the type of controller. You do have to make sure the batteries are working and you do have to add scent to the top of it to attract the deer. The link below will take you to more information and a link to read reviews.
The Yard Sentinel
"The Yard Sentinel Pest Animal Control Repeller is an indoor/outdoor pest repeller that combines heavy alarm power, flashing strobe lights and a loud ultrasonic sound. This digital unit encompasses every proven pest repelling technique currently known, all while remaining affordable. This is considered a motion scare controller.
Unlike many other ultrasonic devices, the Yard Sentinel Pest Animal Control Repeller uses motion detection technology that prevents the unit from operating unless activated. This reduces the ability of the pest animal to acclimate to its powerful sound and strobe features, making it effective for a much longer period of time. The ultrasonic sound can be adjusted for maximum efficacy without disturbing anyone around you. That, coupled with the brighter strobe light and pounding intruder alarm keeps pests as bay from sensory overload."
This unit comes with a four-function remote control, which allows you to set and adjust this unit from the comfort of your own home, making pest control a breeze. If you are in the market for the best in pest control, no matter what pest it is, then this is the unit for you.
Here’s what our customers have to say about the Yard Sentinel Pest Animal Control Repeller: This unit is fantastic! I had a problem with mice, but no more. I haven’t seen any evidence of a mouse in my house since I installed this unit. Two thumbs up!
HERD Electronic Deer Repellent
This is an economical and effective solution that uses patented technology to protect property from deer damage by luring deer and then delivering a mild, harmless electric shock to the animal. This shock conditions the deer and repels them from the protected area. The repellent delivers 400 volts (substantially less then a static shock) and has virtually no amps so is completely safe for use around children and pets. The attractant is included and placed in the head of each electronic rod to lure the deer. Three electronic rods are provided protecting approximately 1,200 sq. ft. of total area. Attracts deer to posts with a lure scent, and harmlessly repels them from your yard with less volts than regular static electricity.
the motion sensor on this DeerChaser® activates, causing it to sound a loud, high-frequency noise, and flash a bright 2-LED light; continues for 2-15 minutes (adjustable) past the last motion detected. Senses movement in a 120? area, up to 25' away. Works day and night. Safe around pets. Three "D" batteries (not included) last up to three months, depending on activation length and setting. Weatherproof housing includes mounting bracket, and measures 4"x10-14".
uses radio and computer technology to operate LP gas cannons. It is marketed as the best wildlife deterrent on the market today because the cannons only go off when a deer or other wildlife is sighted. This way the deer never get used to it going off. Because of expense, it is suggested for commercial nurseries and orchards.
These devices emit an ultrasonic pulse that startles deer. The timing, duration and frequency of the sound changes randomly so deer don't get used to any particular sound
Yard Guard Ultrasonic Deer Repeller
This electronic yard protector keeps animals away from your property without messy or expensive chemical solutions and provides coverage up to 4000 square feet. Proven sound technology repels a number of unwanted pests. Motion sensor triggers ultrasonic blasts in battery mode to save battery. Repels dogs, cats, deer, raccoons, skunks,deer, and other pests. Adjustable frequencies for different pests.
Critter Blaster Pro
Electronic Animal Repellent</strong>-Probably best suited for commercial use, but could be used in urban areas, the Critter Blaster electronically produces eight different sounds of animals in distress or sounds that harass animals and keep them away. It was designed for farms, vineyards, and other large commercial producers. Critter Blaster is
programmable and constantly changes the noises it produces. Said to repel deer, raccoon, dogs, foxes, rodents, and other critters. Has adjustable volume controls, four speakers, and runs on electricity.
Do It Yourself
The following is an excerpt from an internet article on building your own deer sensor.
My original "Deer Repellent/ Seismic Sensor" recommended using a speaker with a weight glued to the cone as a vibration sensor (see bottom of page) but it recently occurred to me that the speaker could supply the mass itself. ...........It will take a minute or so before the circuit reaches full sensitivity. But then the slightest jarring of the jar will ring the bell! The circuit will take a while to recover after a trigger, too. To protect a large area with the sensor set it over a pipe buried just beneath the surface. A footstep anywhere along the pipe will shake the sensor.