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.
Scare Devices
The Guardener
One choice is the Guardener because of it's two modes of scaring the deer and the ability to move it around. These are hard to find to buy but The Scarecrow is about the same and is easy to find. Plus you can get if from places were it can be returned if there are any issues.
GuardenerTM is equipped with 2 ways to deter deer. First, it issues an ultrasonic alarm which can only be heard by the animals, and a pressurized water jet that will scare the deer. The device uses a motion sensor to detect the presence of nearby animals. You can set the detecting area by adjusting the sensitivity knob. Detection range can be adjusted from 15 to 25 feet. Different weather conditions may slightly alter ranges.A unique feature of The Guardener is that it uses both ultrasound and water blast to repel animals. The sprinkler can rotate up to 170 degrees and shooting pressurized water as far as 17 to 22 feet. It has a built in tank that can hold about 3.5 gallons of water. It is solar powered so there is no need for electricity or batteries.
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.
Witeless Deer Fence
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.
Havaheart 5250
The Yard Sentinal Here is a video that show you how the Yard Sentinal works.
"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.
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!
The Scarecrow™ - This motion-activated sprinkler attaches to the garden hose. Just hook it up to your garden hose, plug in the 9-Volt battery and then place the stake in the ground near area to be protected. When an animal is seen, a valve opens, and instantly releases a three-second pulsating spray of water. The combination of the sudden noise, movement, and water frightens animals away. It's clean and an alternative to repellent, but is limited to the distance the water can spray. Both a pro and con is that it is motion activated sensing motion and heat the same way security lights work. This motion could be deer, your dog or cat, or you. One scarecrow can cover up to 1,000 square feet.
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.
DeerChaser® 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".
Scare Wars® 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.
Ultrasonic Units
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-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.