Mammal Damage

Problem type: Miscellaneous

Name of problem: Mammal Damage

Plant name(s): All plants

Symptoms / Characteristics:
Leaves can appear torn, ragged or completely stripped, flower beds may be trampled and young plants may have their terminal or lateral shoots cut off. Bark on woody plants may be chewed, which can girdle a stem or branch, causing growth above the wound to die. Bark damage usually occurs in the winter, when food is scarce. Pests such as gophers may eat roots, resulting in dieback of plant tops. Chewing marks found on wood, around plumbing pipes and other structures may indicate mice or rat activity. Droppings may be present near the area of damage. By observing the size and type of droppings left behind, the type of mammal causing the damage can be determined.

The amount of damage caused by mammals depends on seasonal factors, weather conditions, availability of alternative foods, plant palatability and population levels. Deer damage for example has become more of a problem in urban communities because population levels have more then doubled in recent years.


Control / Preventions:
Caging - For plants that are valued, cages can be put up around plants, using mesh fencing or containers. This can also be done to protect the bark of woody plants in the winter.

Repellents - Commercial animal repellents are available for most animals including rabbits, deer and mice. Reapplications may be needed, especially after a rain. Human hair and Zest, or Irish Spring soap repels rabbits, squirrels and deer. Spread around plants or hang from trees in an old nylon stocking. Homemade repellents can be made by mixing 2 tablespoons liquid dish soap, 1 teaspoon garlic powder and 1 gallon of water.

Barrier Plants - Planting sharp, prickly plants around the perimeter can help keep larger animals out. Rabbits dislike garlic, onions, marigolds and other highly scented plants. Barrier plants work best when placed in front of other plants to deter pests.

Fencing - Fences to keep deer out must be at least 8 feet high. Fences for rabbits need to be 4 feet high and partially buried in the ground (about 1-2 feet).

Birds - Noisemakers and visual scare devices are useful in scaring birds away but should be moved around as the birds can become accustomed to them. Plastic owls are available for bird scaring devices. Streamers, flags and shiny materials such as aluminum foil can be hung from trees and will scare birds when moved or blown in the wind. To avoid attracting large birds, lower the sunflower seed content in birdseed.

Squirrels - Mothballs, traps and baits can be used to control squirrels. Aluminum foil can be wrapped around a tree trunk with a flap at the top as a trunk guard.

Cats - Spreading pruned branches from prickly plants around plants or using coarse materials like straw or woodchips can help deter cats. Sprinklers with a motion sensor to spray water when movement occurs can be useful.

Cat/Rabbit - Blood meal can be spread around plants or a homemade recipe can be used to spray on foliage. Mix ½ teaspoon cayenne pepper, ½ teaspoon chili powder and 1 teaspoon of liquid dish soap in a spray bottle with water, and spray on plants.

Small invaders such as rabbits and mice rely heavily on vegetative cover for protection. By removing this type of cover, these animals will look for a more suitable place to inhabit. Creating an unfavorable environment for invading pests will lower the chance of encountering problems with them.