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Deterring deer

Deterring deer

Deer grazing on plants, shrubs, trees and crops can cause significant damage and a number of methods of deterring this behaviour have been tried. Controlled experiments are limited to proprietary compounds applied to plantation forests. As a result, much of what is known is drawn from the personal experiences of gardeners, foresters and nursery managers. The following list includes some suggestions that fall into the ‘folkore’ category.

Chemical repellents are regulated in the UK by the Control of Pesticides Regulations 1986 and the Control of Pesticides (Amendment) Regulations 1997. Rather bizarrely, lion dung and human hair (two oft quoted deer repellents) fall under the control of these regulations and have not been approved for use as pesticides!

Chemical repellents fall into two broad categories: barrier repellents, which provide a ‘chemical fence’ to deter deer and are applied around the area to be protected, and feeding repellents, which are applied to individual plants to prevent deer feeding.

Barrier repellents

Creosote - Although not intended as a barrier against deer, some gardeners have reported success when hanging creosote-soaked rags around their gardens. Unfortunately, just as many gardeners have reported its inefficacy.

Note: Since 2003, it has been an offence for the general public to purchase and apply Coal Tar Creosote. However, the product is still available for sale to professional users such as the agricultural community and builders providing they do not resell to the general householder.

Diesel soaked cloth strips – Readily available and cheap, this is as good, if not better, than anything else. Place garden canes in the ground, about 20 feet apart, with three or four feet protruding out of the soil. Link the canes with string and from these hang strips of cloth (old flannelette sheets are good) around 12” x 2” which have been soaked in diesel fuel. You don’t want it dripping but moist. As diesel is a bit smelly you should wear rubber gloves when handling.

Human hair - Unwashed human hair stored in tights or muslin and hung in bushes at deer head-height. Success has been highly variable and effectiveness is thought to be reduced by rainfall and age. It is considered best to replace human hair monthly. Controlled experiments have found human hair to be ineffective in protecting areas of plantation forest.

Lion dung - In its raw state lion dung is incredibly smelly and difficult to degrade and has been shown to be ineffective in deterring deer. However, a pelleted form is marketed as a cat repellent and some users have suggested that it also deters deer. Tests are being carried out to establish whether a concentrated liquid extract of lion dung will keep deer out of silage fields.

Scented soap - Hanging bars of heavily scented soap amongst plants is thought by some to be effective. A benefit is that soap does not need to be replaced until it has completely dissolved. Evidence comes from a limited number of uncontrolled trials and suggests variable success.

Mothballs - Not designed as a deer deterrent and totally ineffective.

Human urine - Problems of collection and application of sufficient quantities aside, human urine loses what effectiveness it may have after rain. Again, evidence for its efficacy is limited to anecdote and a few uncontrolled trials.

Feeding repellents

These work by rendering potential food plants unpalatable. Commercially available compounds can be expensive although trials have shown most to be effective, especially for low-density deer populations. However, some need regular re-application, especially after rain, and toxicity may be a problem in gardens.

Visual and sonic deterrents

In general neither sonic nor visual deterrents work. Deer soon get used to sirens, scarecrows, streamers etc. However, deer damage has been reported to be limited in the direct beam of security lights, although they do not prevent entry by deer altogether. Motion-triggered devices that squirt a jet of water or activate a sonic alarm and flashlight are available.

Physical barriers

In short, so many problems and limited efficacy are associated with deterrents that they generally do not provide protection from deer damage under all, if any, situations. The only effective barriers against deer are properly erected and maintained deer fences and individual tree/plant guards.

Minimum specifications for deer fences

Species    Mesh size (mm) Height (m)
Muntjac/CWD 75 x 75 1.5
Roe 200 x 150 1.2
Fallow 220 x 200 1.5
Red/sika 220 x 300 1.8

Further reading

H W Pepper Forest Fencing (1992) Forestry Commission 102 – can be downloaded from www.forestry.gov.uk
Protection of Trees from Mammal Damage by Roger Trout & Andy Burnt (Revised 2014) – download from www.forestry.gov.uk