Vertebrate Animal Pest Control Study Manual

iii

HOW TO USE THIS MANUAL

This manual is divided into three chapters. Chapter 1 introduces three themes. The first

theme addresses the principles of vertebrate pest management. Second, awareness of federal,
state and county laws are brought to your attention. Third, there is a brief discussion on
diseases humans can contact from wildlife.

Chapter 2 covers pest species found in Utah which have some type of commercially

available restricted-use pesticide that can be used to control their damage. There is a brief
description of the physical characteristics of the animal to aid you in identifying the animal
causing the damage. Also, the habitat and food habits of the species are described.
Understanding this information will provide insight into why these animals use certain areas,
and may greatly assist in controlling any damage they may cause.

The "General Biology" section provides information about the breeding behavior to

help you identify the most effective time in which to begin a control program. The "Damage
Identification" section briefly discusses common problems associated with specific animals.
This section provides information to help you identify common signs of the animal. The
"Legal Status" of the species is also discussed. Finally some "Alternatives for Control" are
covered. In this section, the control methods are split into "non-lethal" and "lethal" methods.
Non-lethal methods are emphasized and encouraged. Possible control methods are not
discussed, nor are combinations of programs explored. Each control situation is different and
requires the careful review of all methods appropriate for the control of pest damage.

Chapter 3 provides a general discussion of commonly used non-lethal techniques and

their applications.

By reading this manual you will have gained a sufficient knowledge to pass the Utah

Vertebrate Animal Pest Control Applicators Certification and Recertification Examination.

INTRODUCTION

Vertebrate pest control deals with animals possessing a backbone. Vertebrate pests

include any vertebrate, native or introduced, domestic or wild, which affects human health,
well-being, or conflicts in some way with human activities. This conflict can be either real or
perceived.

Vertebrate pests may include very diverse groups of animals including: amphibians,

reptiles, birds, and mammals. Except for commensal rodents and birds, it is not appropriate to
characterize all wildlife as pest species. Wildlife, for the most part, are considered pests only
in some situations and may be neutral or highly desirable in others.

The primary objective of vertebrate pest management is to alleviate the damage

problem, not destroy the animal. Many vertebrate pest problems can be solved by applying
preventive controls such as sanitation, exclusion, and habitat modification.

Each situation must be handled on an individual basis allowing for a variety of factors.

Analyzing what species is causing the problem before carrying out control measures is the
first step of the process. A combination of control measures will generally yield more positive
results than the use of any single treatment.

This manual does not discuss all the possible problems and pests, or all the known

control methods for dealing with vertebrate pest problems in Utah. For more information
applicators are encouraged to obtain a copy of the handbook: Prevention and Control of
Wildlife Damage

from the Cooperative Extension Service, University of Nebraska, 202

Natural Resources Hall, Lincoln NE 68583-0819, or contact your Utah State University
County Extension Office.

TABLE OF CONTENTS

Chapter 1, Principles of Vertebrate Pest Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

General Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Laws and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Federal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
County and Local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Landowner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Wildlife Disease and Humans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

General Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Sylvatic Plague . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Rabies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Rocky Mountain Spotted Fever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Tularemia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Trichinosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Hantavirus Pulmonary Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Birds and Public Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Histoplasmosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Vertebrate Pest Damage Management and the Public . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 2, Identification and Management of

Vertebrate Pest Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Rodents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Ground Squirrels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Prairie Dogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Pocket Gophers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Woodrats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Voles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
White-footed and Deer Mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Commensal Rodents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Birds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

American Crow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Black-billed Magpie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Blackbirds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
European Starlings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Pigeons or Rock Doves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
House or English Sparrow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

TABLE OF CONTENTS (CONTINUED)

Chapter 3, Non-lethal Management Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86

Suggested Field Guides / Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Supplies and Suppliers Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
First Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
Utah Agricultural Field Representatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

Chapter 1

PRINCIPLES OF VERTEBRATE

PEST MANAGEMENT

SECTION I

GENERAL PRINCIPLES

Although each vertebrate damage situation is different, a standardized approach may

be used to resolve each situation. These approaches or principles describe steps used in
making responsible decisions while addressing specific vertebrate damage situations. The
principles are: 1) Recognize the damage patterns and the species responsible, 2) understand
the biology of the pest species relative to the damage problem, 3) know the damage
management strategies and alternatives, and, 4) know appropriate local, state, and federal
laws.

PRINCIPLE 1:

RECOGNIZE DAMAGE PATTERNS AND SPECIES
RESPONSIBLE

Most damage is caused by a few individuals in a population. It is important to

recognize the damage early and the animal causing it. Early detection can result in reduction
or elimination of the damage at a stage when it may be less expensive to control. It will also
affect fewer animals and use smaller amounts of pesticides or lethal methods.

Delayed control efforts may result in habitat conditioning. This may make the site

more attractive to additional animals and future damage. An example of habitat conditioning
is the construction of burrow systems by ground squirrels, prairie dogs, and pocket gophers. If
an extensive burrow system is present before management is initiated, the conditioned sites
become more attractive to dispersing animals than non-disturbed sites.

Proper identification of the species causing the damage is essential. Damage

management techniques differ for different species both from the legal and practical
standpoint. Assistance in correctly identifying the animals causing damage can be obtained
through USU County Extension Offices or the USU Extension Wildlife Specialist.

PRINCIPLE 2:

UNDERSTAND THE BIOLOGY OF THE VERTEBRATE PEST
RELATIVE TO MANAGING THE PROBLEM

Each potential vertebrate pest species varies in behavior, distribution, food habits,

feeding ecology, habitat requirements and life history. Vertebrate pest populations fluctuate
according to environmental conditions. Many species can also change their normal population
parameters to compensate for the loss of individuals. Given these differences and responses in
vertebrate pest populations, these factors need to considered for control efforts to be effective.

Animals that reproduce seasonally exhibit annual cycles. During the reproductive

period, birth rates exceed death rates and the population increases. When reproduction ceases,
death rates increase and the population declines until the next breeding season. Population
changes of two- to five-fold are not uncommon within the yearly cycle. Factors that affect this
sequence of events may include immigration (new animals moving into an area), dispersal,
weather, habitat disturbances, disease, and predation.

Vertebrate populations respond to the removal of animals in a given area with

increased birth rates, reduced death rates and/or reduced dispersal.

Damage caused by vertebrate pests fluctuates with population size. Damage is seldom

a problem when populations are low. During peaks, damage may be severe and require
frequent attention.

Factors that Affect Wildlife Damage

Weather: If populations are high, damage increases markedly during a dry growing

season. Damage to crops is reduced during years of abundant moisture and when native
forage is available.

Seasonal Movement: Damage may coincide with seasonal migrations of big game

herds, waterfowl, cranes, and blackbirds. Migrating birds may have the greatest impact on
ripening crops in late summer and fall.

Duration, season, and daily activity patterns: Knowledge of the duration and season

of the damage impact and the activity patterns of the pest are important in determining the
degree of control needed. Protecting tree seedlings from damage by deer browsing may be
necessary for 6 months during each year for a decade, whereas protecting grain from
waterfowl damage may be only necessary for 2 to 3 weeks every other fall. Keeping raccoons
out of a garden by using electric fencing requires that the fence only be turned on at night.

All species exhibit unique requirements and life patterns. The more information you

have regarding a species and its requirements, the more effective your management program
will be.

PRINCIPLE 3: KNOW THE ALTERNATIVES

With increasing regulations and restrictions, there are many management options that

need to be considered prior to implementing a damage management program. Management
options include toxicants, trapping, and habitat and behavior modification. Each option has
advantages and disadvantages, costs, and efficiency levels. Each option works well under
certain conditions, and poorly in others. All options require some level of training,
persistence, commitment, and risk on the part of the applicator.

Every option should be considered when formulating a vertebrate pest damage

management strategy. Options that minimize the use of pesticides are the real backbone of
integrated pest management.

PRINCIPLE 4: KNOW THE LAW

Knowledge of, and compliance with local, state, and federal regulations regarding the

use, storage, disposal, and record keeping of pesticides used in vertebrate pest control
programs is essential. The use of the pesticides in manners not consistent with label
instructions can increase the risks to non-target species or result in ineffective control
programs. The improper use of pesticides can also result in fines, loss of the use of the
chemical as a management option, not to mention the bad publicity.

SECTION II

LAWS AND REGULATIONS

All wildlife living within the state of Utah, that are not held by private ownership and

legally acquired, are the property of the state. Wildlife by definition include, crustaceans,
insects and all vertebrate animals living in nature, with the exception feral animals. As a
publicly owned resource, wildlife are protected by state and federal laws.

Prior to beginning any vertebrate pest damage management program the legal status of

the animal must be determined. An animal's legal status will influence the selection of
management techniques. The Utah Division of Wildlife Resources (UDWR), Utah Depart-
ment of Agriculture (UDA), U.S. Fish and Wildlife Service (USFWS), and U.S. Department
of Agriculture--Animal Plant Health Inspection Service / Animal Damage Control (USDA-
APHIS/ADC) are the state and federal regulatory agencies that can be contacted regarding the
laws concerning wildlife's legal status and vertebrate pest damage management.

Any individual or organization planning to manage a vertebrate pest problem should

understand all the federal and state laws, as well as any county or city ordinances that may
pertain to the animal.

FEDERAL

United States Department of Agriculture

The U.S. Department of Agriculture--Animal and Plant Health Inspection Service

Animal Damage Control (USDA-APHIS/ADC) is the federal agency authorized to carry out
predator, bird, and rodent control activities in order to protect American agriculture. These
activities are conducted in cooperation with the Utah Department of Agriculture. This
authority is stated legislation, enacted by the United States Congress on March 2, 1931 (46
Stat. 1468), on August 14, 1946 (60 Stat. 1080), and on December 19, 1985 (Public Law 99-
190).

United States Fish and Wildlife Service

The USFWS is responsible for the administration of the Endangered Species Act of

1973 (16 U.S.C. 1531-1543; 87 Stat. 884) as amended, the Fish and Wildlife Act of 1956 (16
U.S.C. 742a-742: 70 Stat. 1119) as amended, and the Migratory Bird Treaty Act of 1918 (16
U.S.C. 703-711; 40 Stat. 755) as amended (Part 21--migratory bird permits and control of
bird depredation). These laws give the USFWS the regulatory authority to prevent or restrict
activities which may affect a protected wildlife species.

STATE

Utah Division of Wildlife Resources

The Utah Legislature has declared wildlife property of the state. To manage the state's

wildlife resources, the legislature created the Division of Wildlife Resources (UDWR) within
the Department of Natural Resources (DNR). UDWR is under the administration and general
supervision of the executive director of the DNR. It is subject to the policy-making authority
of the Utah Wildlife Board and the Utah Board of Big Game Control and charged with the
duty to protect, propagate, manage, conserve, and distribute protected wildlife throughout the
state. The coyote, red fox, field mouse, gopher, ground squirrel, jack rabbit, muskrat, raccoon,
and striped skunk are not considered to be protected wildlife. The director of UDWR may
authorize removal of big game animals and beaver that are damaging private property.
UDWR is also authorized to compensate crop owners for actual damage attributed to big
game and pheasants.

Utah Department of Agriculture

The Utah Department of Agriculture administers and enforces the Utah Pesticide

Control Act (Title 4, Chapter 14). This Act regulates the safe and proper use of pesticides,
regarding vertebrate pest damage management and certification of applicators. Pesticide pro-
duct labels are registered by the Utah Department of Agriculture under Section 6 of the Act.

COUNTY AND LOCAL

Utah counties and municipalities may affect local urban vertebrate pest damage

management efforts. Each entity may enact laws or ordinances that govern the use of specific
techniques. For example, it is unlawful to discharge a firearm within city limits. Some cities
may also restrict the use of traps or toxicants.

LANDOWNER

The Utah Agriculture and Wildlife Damage Prevention Act (Title 4, Chapter 23) gives

landowners and legal occupants (tenants) the authority to destroy animals found in or near
buildings on their premises when those animals are destroying property including trees and
crops. Any agent engaged by the landowner or tenant is also authorized to operate under that
law. Animals that have been destroyed cannot be taken into possession, sold, or utilized by
the landowner, tenant, or agent. Destroyed animals must be taken into possession and
disposed of by UDWR employees. Damage caused by wildlife under these guidelines must be
substantial and excessive. Incidental or inconsequential damage does not constitute sufficient
justification to warrant the animal's destruction. The UDWR ultimately must determine if the
landowner, tenant, or agent has exceeded authority to protect property. This state law is not
applicable to federally protected species.

SECTION III

WILDLIFE DISEASE AND HUMANS

Wildlife populations can serve as a reservoir or carrier for diseases that may affect

humans. People who undertake control programs or are in frequent contact with wildlife
should be aware of these diseases and how to take precautionary or preventative measures to
protect themselves. This section discusses some diseases that wildlife carry that can affect
humans.

GENERAL PRECAUTIONS

The risk of human infection for diseases that are carried by wildlife can be

significantly reduced by taking some simple precautionary steps.

Avoid wild animals that are sick or behaving abnormally; this includes animals that
have lost their fear of humans.

Always wear rubber gloves when skinning or examining any wild animal.

Practice cleanliness when working with wildlife. Do not eat or drink while handling or
skinning animals and wash hands thoroughly when finished.

If you become sick after working with an animal, tell your physician immediately that
you have encountered or handled a wild animal.

SYLVATIC PLAGUE

Sylvatic plague is an acute infectious disease that causes fever and swelling of the

lymph glands.

Four basic components seem to be involved in the spreading of sylvatic plague. These

are 1) fleas, 2) soil, 3) hibernating rodents, and 4) varying degrees of susceptibility among
rodent populations. Fleas (Yersenia pestis) are the principal vectors in transmitting the
disease. The structure of burrow systems and the social behavior of wild burrowing animals
create favorable conditions for these fleas and sylvatic plague to spread.

Transmission of sylvatic plague is dependant upon fleas feeding on an infected animal

and then feeding on an uninfected individual. Plague can affect many species of wildlife such
as ground squirrels, wood rats, prairie dogs, chipmunks, marmots, rabbits, deer mice, voles,
and badgers.

RABIES

The rabies virus persists in the salivary glands of animals; from there it spreads when

an infected animal bites another animal or human. The virus attacks the brain and spinal cord.

If not treated immediately, rabies is fatal in humans. Treatment consists of a series of

vaccinations. The efficiency of the treatment is dependant upon the length of time that has
passed since exposure. By the time clinical symptoms develop, it is too late to save the
patient. If a human is bitten, the offending animals must be sacrificed immediately in order to
confirm the presence of rabies. Without benefit of this diagnosis (other than the bite itself) the
victim must undergo the series of vaccinations.

The disease manifests itself in two strikingly different forms of behavior:

furious/aggressive

and paralytic rabies. In the furious form, the typical "mad dog" symptoms

are expressed, with the victim running around, biting and snapping at other animals or
inanimate objects. Hoofed animals may bite and lash out with their legs, and infected birds
attack with their beaks. In the less common paralytic form, animals become semi-paralyzed,
they drop their jaws, and cannot bite or produce sounds.

Skunks, foxes, bats, and raccoons are common wildlife reservoirs of rabies.

Prevention and Control

Effective rabies prevention should be based on 1) vaccination of domestic animals, 2)

control of stray dogs and cats, and 3) public education.

ROCKY MOUNTAIN SPOTTED FEVER

Rocky mountain spotted fever is caused by a microorganism (rickettsial) and is

transmitted only by ticks. It has been isolated from a wide variety of wild animals in the
United States. At least nine species of ticks have been found to be naturally infected with the
disease, although not all are known transmitters to humans. These various species of ticks are
adapted to habitats ranging from human dwellings to forests, mountains, and plains, and from
humid to arid climates. The disease occurs in persons that have been bitten by an infected
tick. Infection may also be contracted from ticks by crushing them. Persons who spend a
considerable amount of time outdoors such as hikers, campers, sheep herders, surveyors,
explorers, soldiers on maneuvers, and forest workers are at a greater risk of infection. Owners
of dogs and cats may become infected where suitable host ticks are abundant.

Rocky mountain spotted fever can be treated effectively by a physician, particularly if

the disease is diagnosed early. In case of illness, any recent history of the tick bite should be
related to the physician. Vaccines are available to control the disease and should be limited to
those who are exposed by reason of occupation or residence in tick-infested areas where the

disease is known to occur. Campers and hikers entering infested areas should employ
appropriate measures to reduce the risk of tick bite. Measures should include the use of
repellents and proper clothing.

TULAREMIA

Tularemia is a bacterial, plague-like disease that exists in rabbits and rodents. It is

transmitted by an ectoparasite or direct contact. It is commonly transmitted to man from
infected rabbits, primarily cottontails, through an open wound during the process of skinning
the rabbit. Tularemia may also be contracted from improperly cooked meat or through bites of
ticks and flies.

Rabbits with tularemia behave oddly, run slowly, and can often be captured quite

easily. They may appear tame or to be in a stupor. Rodents, such as beaver, muskrats, and
voles, have some susceptibility to the disease under certain conditions. Tularemia in rabbits
and rodents cannot be eradicated. Attempts to reduce the numbers of susceptible wild hosts
are generally ineffective at reducing the incidence of the disease.

TRICHINOSIS

Trichinosis results from an infection in the intestines and muscles by larvae and cysts

of Trichinella spiralis. Infection occurs when a host eats raw or improperly cooked meat that
contains the larvae or cysts. Evidence indicates that all mammals are susceptible to infection
with this parasite but it's most common in wild carnivores and scavengers. Research also
indicates that hogs, who were experimentally fed trichina-infected feces of rats and mice,
readily become infected. This suggests that rodents may play a role in the spreading of
trichinosis to hogs fed on garbage containing infected rat or mice feces. If the meat of
carnivorous wildlife, scavengers or hogs is consumed by humans, it should be properly
prepared by cooking, freezing, or curing to destroy any viable larvae or cysts.

HANTAVIRUS PULMONARY SYNDROME

Hantavirus pulmonary syndrome (HPS) is a recently recognized disease of the lungs.

The disease is characterized by flu-like symptoms, usually fever greater than 100, muscle
aches and chills, followed by difficulty in breathing. The disease results from exposure to
rodents.

Hantavirus infection is spread by inhaling the virus. These airborne viruses may come

from rodent droppings, urine and saliva. The disease is spread from rodent to rodent through
bites and, although uncommon, can be passed to humans in this manner. The common deer
mouse (Peromyscus maniculatus) appears to be responsible for the spread of the disease in
most of the U.S. Other rodents are also infected with this virus but in much smaller numbers.

The incubation period is not well known. HPS should be considered in anyone with

any flu-like symptoms who has had exposure to rodents within the last 42 days. Avoiding
contact with any rodent species is the only prevention.

BIRDS AND PUBLIC HEALTH

Large roosting colonies of birds can lead to public health problems. Droppings, in

addition to creating an objectionable smell, form a medium for the growth of bacteria and
fungi. Birds may also serve as carriers or vectors for disease. Large concentrations of birds
roosting or feeding near airports also create aviation hazards for private, public, and
commercial aircraft.

HISTOPLASMOSIS

Histoplasmosis is a respiratory disease in humans caused by inhaling spores from the

fungus Histoplasma capsulatum. Areas where bird droppings are abundant are ideal places for
the growth of the fungus. Infection by only a few spores generally produces a mild case of
histoplasmosis in humans and most are unaware that the disease has been contracted. A more
severe infection may result in an acute pulmonary infection with symptoms much like the flu.
The patient generally recovers spontaneously after a period of several weeks. Serious
infections can result from massive spore inhalation. Such cases may be chronic and are
generally treated with amphotericin B. Infection can be detected through a skin reactivity test
or lung x-ray which reveals healed lesions.

Chapter 2

IDENTIFICATION AND MANAGEMENT OF

VERTEBRATE PEST DAMAGE

SECTION I

RODENTS

GROUND SQUIRRELS

Description

The Richardson's ground squirrel (Spermophilus richardsonii) is light grayish brown

tinged with brown or buff (Figure 1). They have black speckles that result in a spotted or
barred effect and are indistinctly mottled with a whitish or pale buff underside. The body
measures about 8 inches long with a 2 to 4 inch tail. An adult weighs from 11 to 18 ounces.
The Richardson ground squirrel is the most common ground squirrel found in Utah.

The Columbian ground squirrel (Spermophilus columbianus) is easily distinguished

from other ground squirrels in its range by its distinctive coloration. It has reddish-brown fur
on its nose, forelegs and hindquarters. The head and body measure 10 to 12 inches in length
with a 3 to 4 inch tail. An average adult weighs more than 1 pound.

Food Habits

The Richardson's ground squirrel is common in areas of open sagebrush. It is often

found on dry farms and grasslands. The Columbian ground squirrel is found in wetter areas
such as meadows, irrigated pastures, and alfalfa fields.

Ground squirrels feed on green vegetation (grasses and forbs) when available, and

switch to dry grasses and seeds later in their active period. The relatively high lipid content of
the seeds aids in the deposition of fat necessary for hibernation in all ground squirrels.

Legal Status

Richardson and Columbian ground squirrels in Utah are not protected by state law.

Alternatives for Control

NON-LETHAL

Exclusion:

Exclusion is generally not practical for control of ground squirrels.

Cultural Methods:

These methods are generally not practiced for control of ground squirrels.

Repellents:

None are registered by the EPA or the State of Utah.

LETHAL

Toxicants:

Baiting with 2% zinc phosphide grain baits is the most effective population
reduction method for ground squirrels. Late fall or early winter is the best time
to use poison grain baits. Oats are the preferred grain bait. Begin the baiting
operation during stable good weather periods. Pre-bait each burrow with
untreated oats. After 2 or 3 days, if the untreated bait is eaten, treat the entire
colony.

When scattering grain, apply the amount indicated on the product label on the
hard, clean ground around the burrow. The bait should be scattered over a 1-
square foot area near the burrow entrances. Do not place the grain inside the
burrow entrance, on the mound, or in the grass away from the mound. Do not
put the grain in lumps or piles. If the grain is scattered well, the risk to livestock
is minimal. The safest way to avoid poisoning livestock is to treat only pastures
where livestock have been removed.

Fumigants:

Aluminum phosphide can be used for ground squirrels surviving the use of
poisoned grain baits can be controlled using a burrow fumigant. Fumigate only
burrows known or strongly suspected to be occupied. Mark all burrows to be
treated with wooden stakes or engineering flags. As the burrows are treated the
markers can be removed. After fumigating, the burrow should be closed with
soil or sod to seal in the gas. If any burrows are reopened or activity is noted
after treatment, they should be re-fumigated.

Figure 2. Utah prairie dog (Cynomys parvidens).

PRAIRIE DOGS

Description

There are three related species of prairie dogs in Utah: white-tailed prairie dog

(Cynomys leucurus), Gunnison's prairie dog (Cynomys gunnisonii) and Utah prairie dog
(Cynomys parvidens). The white tailed prairie dog is buff mixed with black (Figure 2). The
Gunnison's prairie dog is a cinnamon-buff color but darkest in the mid-torso area. Utah
prairie dogs are cinnamon or clay colored with a mixture of buff and black-tipped hairs, and
slightly darker on the rump. All have dark patches above and below the eye. Adult prairie
dogs weigh from 1½ to 2½ pounds. Utah prairie dogs occur only in Iron, Garfield, and
Wayne counties of Utah.

Food Habits

Their diet consists primarily of green plants such as bluegrass, bromegrass, grama

grass and alfalfa. They occasionally eat insects such as grasshoppers, but rarely eat meat.

General Biology

Prairie dogs are social mammals that live in colonies. Their "towns" may consist of

several individuals and cover 200 acres or more. Burrows have sleeping chambers with nests
made of dry grass, and excrement chambers that are buried when filled and new ones made.
Holes are linked to provide for air passage. There may be as many as 8 to 15 burrow openings
per acre. All white-tailed prairie dogs hibernate. They enter hibernation in October and
emerge in late February to early March.

The prairie dog breeding season is from March through May. After a 30 day gestation

period a litter of three to six blind and hairless young are born. Foxes, badgers, coyotes,
hawks, owls, and snakes are primary predators of prairie dogs in Utah.

Damage Identification

The most conspicuous signs of prairie dog activity are the soil mounds that mark

burrow entrances. On gently sloping range lands, the amount of bare soil exposed may cause
increased erosion.

Since prairie dogs eat the same plants as livestock do, they may compete with

domestic livestock for available forage. In alfalfa fields, prairie dogs can reduce yields and
their mounds can damage mowing equipment.

Legal Status

The Utah Prairie dog is listed as a threatened species by the U.S. Fish and Wildlife

Service. However, permits to remove a certain number of animals causing damage in alfalfa
fields are available through the Utah Division of Wildlife Resources on a case by case basis.
The Gunnison's and white-tailed prairie dog are not protected by Utah state law.

Alternatives for Control

NON-LETHAL

Exclusion:

Fencing is generally not practical for control of white-tailed prairie dogs.

Cultural Methods:

Cultural methods are generally not practiced for control of white-tailed prairie
dogs.

Repellents:

No repellents are registered by the EPA or the State of Utah.

Figure 3. Poison grain bait should be scattered over a 1 square foot area
at each burrow entrance.

LETHAL

Toxicants:

Baiting with 2% zinc phosphide grain baits can be an effective population
reduction method for use on prairie dogs. Late fall or early winter is the best
time to use poison grain baits. Oats are the preferred grain bait. Baiting opera-
tions should only be conducted during settled weather periods. To increase the
chance of success each burrow should be pre-baited with untreated oats. After
2 or 3 days, if the pre-bait is eaten, then the entire colony can be treated.

When scattering grain, apply the amount indicated on the product label to the
hard, clean ground around the burrow. The bait should be scattered over a 1-
square foot area near the burrow entrance (Figure 3). DO NOT place the grain
inside the burrow entrance, on the mound, or in the grass away from the
mound. DO NOT put the grain in lumps or piles. If the grain is scattered well,
risk to livestock is minimal. The safest way to avoid poisoning livestock is to
treat only pastures where livestock have been removed.

Fumigants:

Aluminum phosphide can be used on prairie dogs surviving the use of poison
grain baits or inhabiting irrigated alfalfa fields. Fumigate only burrows known
or strongly suspected to be occupied. Mark all burrows to be treated with

Figure 4. Black-footed ferret.

wooden stakes or engineering flags. As the burrows are treated the markers can
be removed. The burrow should be closed with soil after fumigating to seal in
the gas. If any burrows are reopened or activity is noted after treatment, the
active burrows should be re-fumigated.

To increase the fumigant's effectiveness, be sure to read and follow all label
instructions. In general, fumigants tend to be less effective in dry soil.
Fumigation also can fail because of the configuration of the burrow system,
length of the burrow system, absorption of grasses, and gas diffusing into
cracks in the ground, or into interconnecting burrows. Fumigation is expensive,
laborious, and can be disappointing.

NOTE: Prior to beginning a baiting operation, the prairie dog town to be baited should

not be disturbed for an entire season.

Shooting:

Shooting is not very effective for controlling white-tailed prairie dogs.

SPECIAL CONSIDERATION:

BLACK-FOOTED FERRET

The black-footed ferret (Figure 4) is an endangered species. Black-footed ferrets are

found exclusively in prairie dog towns, since prairie dogs are their major prey source. Prior to
beginning a prairie dog control program the site should be evaluated to determine if it meets
federal guidelines for ferret surveys. This is a label requirement for aluminum phosphide. If a
ferret is suspected of inhabiting an area, report its presence to state or federal officials before
initiating any prairie dog control.

Figure 5. Pocket gophers (Thomomys talpoides).

POCKET GOPHERS

Description

There are two species of pocket gophers in Utah: Botta's pocket gopher (Thomomys

bottae

) and the northern pocket gopher (Thomomys talpoides). The species are similar with

thickset bodies, short necks, short fur, small eyes and ears, a naked or sparsely haired tail, and
large externally fur-lined cheek pouches (Figure 5). These "pockets" gave rise to the common
name. The pockets extend from the cheeks to the shoulders, and are used to carry food or
bedding material for nests. Pocket gophers make two kinds of burrows: those near the surface
for food gathering and deeper ones that are used for storage and shelter. The pocket gopher
can move about in its burrow equally well in both the forward and backward directions.
Pocket gophers have large incisors that continually grow throughout the gophers life. In order
to keep dirt out of the mouth while the gopher is underground gnawing and foraging, the lips
close behind the incisors.

Food Habits

Pocket gophers usually forage underground for roots and tubers. They will also cut off

stems below ground and pull the plant into the burrow from below. What is not eaten
immediately is stored in underground chambers for later use. They derive all their water from
the vegetation they consume.

General Biology

Pocket gophers are solitary animals. They do not hibernate but retreat to deep burrows

in winter. Males emerge in the spring to seek mates. After mating they separate.

Gophers give birth to one or two litters per year. Litters range in size from 2 to 11

young. Pocket gophers are sexually mature at 3 months of age but remain in the mothers
burrow for approximately 2 years. When they leave, most go above ground and are very
vulnerable to predators.

Damage Identification

Depending on the condition of local vegetation and the species present, several types

of damage can be attributed to pocket gophers.

Many complaints against pocket gophers stem from damage they do to alfalfa
plants or the nuisance they constitute in those fields.

By eating the roots of alfalfa they can kill entire plants. The mounds of soil
thrown out on the surface of the ground may also kill alfalfa plants and as well
as create a nuisance by plugging and dulling mower cutter bars or windrowers.

Pocket gophers compete with livestock and other herbivores. By harvesting and
burying vegetation, gophers reduce the amount of herbage available for
grazing.

Gophers alter composition of vegetation through selective feeding and soil
disturbance. They tend to suppress plant species on which they commonly feed
and maintain those that benefit from disturbances (usually undesirable
annuals).

Gophers reduce ground cover and sometimes may be the primary cause for
erosion.

Gophers create a nuisance and cause damage to lawns and gardens. They will
eat garden plants and create soil mounds in lawns.

Gophers sometimes cause serious problems in attempts at reforestation of
burned or logged areas. By eating the roots of seedlings, they kill or severely
weaken young trees.

Legal Status

Pocket gophers are not protected by Utah state law.

Alternatives for Control

NON-LETHAL

Exclusion:

Fencing is not practical.

Cultural Methods:

These methods have not proven to be effective.

LETHAL

Toxicants:

Strychnine alkaloid or strychnine grain, milo, oats, or wheat baits are

effective in amounts as low as 0.31 pounds per acre of 0.5 percent strychnine
coated bait.

Zinc phosphide 2% concentration in either pelleted or on grain baits can be
effective in controlling pocket gophers.

These baits must be placed underground. The best way is to open a hole in the
main gopher runway and place a teaspoon of bait inside.

On larger areas, a mechanical burrow-builder can be used to place bait. This
machine will create an artificial burrow and place the poisoned bait in the
burrow at the same time. The burrow-builder is pulled by a tractor to make
parallel burrows about 25 feet apart. These burrows should be at least 9-10
inches in depth.

Fumigants:

Aluminum phosphide is a registered fumigant for pocket gopher control is a
restricted use pesticide. Prior to using be sure to read and follow label
instructions. Aluminum phosphide will affect other burrow dwelling animals.

The best time to use fumigants is in the early spring when soil moisture
conditions are good.

Gas cartridges are commercially available and are not a restricted use
pesticide.

Traps:

Several types of traps are beneficial for small scale control of gardens or lawns.

Traps should be set at "fresh workings." The following steps are recommended:

1. Locate the newest mound in the area.

2. Probe to locate the main runway. Locate the main runway by finding the
plug where the gopher has filled up the lateral tunnel and left a horseshoe-
shaped depression in a fresh mound. The main runway will be about 15 to 18
inches away from the mound on the same side as the horseshoe-shaped
depression.

3. Dig down until you locate the runway and remove soil from the burrows so
that traps can be placed far back into the runway.

4. Attach a piece of wire by running it through the coil spring. Fasten the other
end of the wire to a metal stake to serve as a anchor and to help locate the set
for tending so the gopher cannot pull it into the burrow.

5. Set and place two traps, one in each direction. The trigger is placed away
from the excavation.

6. The open burrows attract the gopher and it will be caught while trying to
plug them. Push traps into the open tunnel as far back as possible or partially
cover the entrances.

Shooting:

Shooting is not practical.

Figure 6. Woodrats (Neotoma stephensi).

WOODRATS

Description

Five species of woodrats occur in Utah. The Bushytail woodrat (Neotoma cinera),

Desert woodrat (Neotoma lepida), Stephens woodrat (Neotoma stephensi), Whitethroat
woodrat (Neotoma albigula) and the Mexican woodrat (Neotoma mexicana). These rodents
are about the size of the common Norway rat or house rat. They are distinguishable from the
Norway rat by their hairy rather than scaly tail, soft, fine fur, and large ears (Figure 6).

Food Habits

The food habits of woodrats are relatively specific for the individual species. For

example, the bushy tail woodrat feeds primarily on green vegetation, twigs and shoots while
the Mexican woodrat feeds on seeds, fruits, acorns, and cactus.

General Biology

Woodrats are usually active at night. Most species build a large stick house on the

ground or in trees while some species live in rocky outcroppings. The houses are typically
occupied by one individual or by a female with her young. Nests are made of finely shredded
plant material located within the larger den. Breeding occurs in the spring. After a gestation
period of 23-28 days, a litter containing one to four is born in mid-March.

Damage Identification

Woodrats are a vector in the transmission of certain diseases, most notably sylvatic

plague. Woodrats are a nuisance around cabins, outbuildings, and other infrequently used
structures. They have a tendency to pack away small objects such as jewelry, cooking and
eating utensils, and other shiny items. This is why they are commonly referred to as packrats.
This behavior can be a nuisance to backpackers and campers.

Populations are fairly dispersed and economic damage to agricultural crops occurs in

limited areas. Agricultural damage occurs when woodrats gnaw small twigs and branches on
forest or orchard trees. Excessive gnawing can result in the damaged tree dying.

Legal Status

Woodrats are protected by Utah state law. They can be controlled when causing

property damage or creating a public health concern. Check with local UDWR or Agricultural
Department Office prior to implementing any large scale control programs.

Alternatives for Control

NON-LETHAL

Exclusion:

Woodrats can be permanently excluded from buildings. Since woodrats are
agile climbers, all entrances to buildings, including those at the attic level, must
be closed. Coarse steel wool, wire screen and lightweight sheet metal are
excellent materials for plugging gaps and holes.

Cultural Methods:

Cultural methods are not generally useful. In orchards, trimming lower
branches of trees may be useful.

Destruction of woodrat dens and nests may also reduce numbers.

Repellents:

There are no registered repellents for woodrats.

LETHAL

Toxicants:

Zinc phosphide is a Restricted Use Pesticide and must be applied by a
certified applicator. Steamed rolled oats or oat groats treated with 1.0% zinc
phosphide are generally very effective on woodrats. Zinc phosphide bait should
be applied in late afternoon just prior to the night-time feeding.

Anticoagulants are baits containing diphacione and chlorophacinore. Open
bait containers are recommended over bait boxes as woodrats may fill the
boxes with sticks and other debris. Anticoagulant paraffin bait blocks have also
proven valuable for woodrat control. Paraffin increases resistance to mold and
lasts longer. Also, the bait block should be tacked or tied down to prevent the
woodrat from taking it away.

Traps:

The standard rat trap or snap type is quite effective for woodrats. Pre-baiting
the trap by leaving it baited but unset for several days will improve trap
success. Good trap baits include bacon rind, peanut butter, oatmeal and raisins.
Nesting materials such as cotton can also provide an effective bait.

Live-catch traps can be used for woodrats using the same baiting procedures
described for snap traps. Trapped animals should be immediately disposed of
and not released in other areas.

Burrow entrance traps such as the 110 Conibear trap can be used in woodrat

control. The trap is placed in nest openings or other restricted travel ways and
is triggered when the wood rat passes through the trap opening. Baiting is not
necessary when traps are set in this manner.

Glue boards can also be effective for trapping woodrats. These work on the
same principle as fly paper; when a rat attempts to cross a glue board, it gets
stuck. This method requires the applicator to devote much time to the
surveillance of the paper because woodrats caught on glue boards may not die
immediately; therefore, it is important to frequently check the boards. Captured
animals should be immediately disposed of. If a live animal is discovered it can
be killed quickly by immersing the entire board in water.

Shooting:

Shooting is not practical for control of woodrats.

Figure 7. Montane vole (Microtus montanus) (left), and Prairie vole (Microtus ochrogaster)
(right).

VOLES

Description

Meadow voles, also called meadow mice, field mice, etc., belong to the genus

Microtus

. Voles are compact animals with stocky bodies, short legs and a short tail (Figure 7).

Their eyes are small and their ears are partially hidden. A vole's underfur is dense and
covered with thick, long guard hairs. They usually are brown or grey, though many color
variations exist.

Five species of voles live in Utah. Tentative identification of a particular animal may

be made by using species descriptions, habitat descriptions and range maps. Descriptions of
each species follow.

PRAIRIE VOLE (Microtus ochrogaster )

The prairie vole is 5 to 7 inches in total length. Its fur is grey to dark brown mixed

with gray, yellow or hazel-tipped hairs, giving it a "peppery" appearance. Underparts are grey
to yellow-grey. It is the most common vole in prairie habitats.

The prairie vole is found in a variety of habitats such as old fields, marshlands and

short grass prairies. When in associated with the meadow vole, it is generally in drier habitats.

MEADOW VOLE (Microtus pennsylvanicus )

The meadow vole is the most widely distributed Microtus species in the United States.

Its total length is 5½ to 7½ inches. Its fur is grey to yellow-brown obscured by black-tipped
hairs. A northern subspecies may also have some red in its fur. Its underparts are grey, at
times washed with silver or buff and the tail is bi-colored.

The meadow vole prefers wet meadows and grassland habitats. When in association

with the montane vole or prairie vole, it is generally found in more moist habitats.

LONG-TAILED VOLE (Microtus longicaudus )

The long-tailed vole can be distinguished from other Microtus species by its tail which

comprises 30% or more of its total length (6 to 8½ inches). It has grey to dark brown fur with
many black-tipped hairs. The underparts are grey mixed with some white or yellow and the
tail is indistinctly bi-colored.

The long-tailed vole is found in a variety of habitats, e.g., sagebrush grasslands,

forested mountain meadows, and stream banks.

MONTANE VOLE (Microtus montanus )

The montane vole is 5½ to 8½ inches in total length. Its fur is brown washed with grey

or yellow hairs, with some black-tipped. Its feet are usually silver grey and body underparts
are whitish and the tail is bi-colored.

The montane vole is found in alpine meadows, dry grasslands and sagebrush grass-

lands. When in association with the meadow vole, it generally occupies the drier habitats.

WATER VOLE (Microtus richardsonii )

The water vole is the largest Microtus species in America. Its total length (nose to tip

of tail) is 8 to 10½ inches. It has grayish-brown fur with grey underparts that are washed with
white or silver. The tail is bi-colored dark above, light below.

The water vole is found primarily in semi-aquatic habitats including stream banks,

lakeshores, and in alpine meadows.

Voles occupy a wide variety of habitats. They prefer areas with heavy ground cover of

grasses, grass-like plants or litter. When two species are found together in an area, they
usually occupy different habitats. Voles have also been known to occupy orchards and
cultivated fields.

Food Habits

Voles eat a wide variety of plants. They most frequently eat grasses and forbs, but in

late summer and fall they will store seeds, tubers, and bulbs to eat during the winter months.
Voles will also eat snails, insects and carrion.

General Biology

Voles are active day and night, year round. They do not hibernate. Home ranges are

usually 1/4 acre or less; however, the size may vary with season, population density, habitat,
food supply, and other factors. Voles construct many tunnels and surface runways with
numerous burrow entrances. A single burrow system may contain several adults and young.

Voles breed several times throughout the year. After a gestation period of about 21

days a litter of up to 11 are born. Young are weaned by the time they are 21 days old, and the
females are sexually mature at 35 to 40 days.

Large population fluctuations are characteristic of voles. Population levels generally

peak every 2 to 5 years. Many voles are excellent swimmers and can evade predation by
swimming and diving. Voles fall prey to coyotes, snakes, hawks, owls, weasels, and are a
major prey source for marten.

Damage Identification

Voles cause damage to orchards and forests by girdling seedlings and mature trees.

Girdling mainly occurs in fall and winter. Field crops (e.g., alfalfa, clover, grain, potatoes),
lawns, and golf courses may be damaged by the extensive runway and tunnel systems voles
build. These systems interfere with crop irrigation by displacing water and causing levees and
checks to wash out.

An extensive surface runway system with numerous burrow openings is the most

easily identifiable sign of voles. Runways are 1 to 2 inches wide with vegetation clipped close
to the ground (Figure 8). Feces and small pieces of vegetation may also be found in the
runways.

The pine vole does not use surface runways. It builds an extensive system of

underground tunnels. The surface runways of the long-tailed vole are the least extensive.

Girdling and gnaw marks alone do not necessarily indicate the presence of voles, since

other animals, such as jackrabbits, may cause similar damage. Vole girdling can be
differentiated from girdling by other animals by the lack of uniformity of the gnaw marks.
They occur at various angles and in irregular patches. The approximate size is 1/8 inch wide,
3/8 inch long, and 1/16 inch or more deep. Rabbit gnaw marks are larger and show neatly
clipped branches with oblique clean cuts. Close examination of girdling damage and the
presence of accompanying signs (feces, traces, burrow systems, etc.) should enable
identification of the animal causing girdling damage.

Voles are not a species which pose a major public health hazard because they rarely

come into contact with humans. However, they are capable of carrying disease organisms

Cultural Methods:

Eliminate ground cover in and around crops, lawns and cultivated areas.

Soil cultivation destroys cover and burrows.

Repellents:

Thiram may be useful for short-term protection. Thiram is a commercially
available fungicide which, when applied to a plant or plant part, will give the
plant a bitter taste.

Live Traps:

Sherman or box traps can be used for live trapping voles. These live traps can
be purchased at local garden or nursery stores.

LETHAL

Toxicants:

Zinc phosphide (2% concentration) is available in pellet and grain bait
formulations. This toxicant can be broadcast at rates of 610 lbs/acre or placed
in runways and burrow openings.

Anticoagulant baits can be broadcast, placed in burrows or put in bait
containers. These baits can be glued to the inside of water-repellent paper
tubes.

Fumigants:

Fumigants are usually not effective for the control of voles.

Traps:

Traps are only effective for controlling small vole populations.

Mouse snap traps baited with a peanut butter-oatmeal mixture or apple slices
may be effective.

Shooting:

Shooting is not practical for the control of voles.

Figure 9. The deer mouse (Peromyscus maniculatus).

WHITE-FOOTED AND DEER MICE

Description

The White-Footed mouse (Peromyscus leucopus) and the Deer mouse (Peromyscus

maniculatus

) are nearly identical in appearance (Figure 9). Identification on the basis of

habitat or consultation with an expert may be the only way to tell the two species apart. The
head and body of the mouse are 3 to 7 inches in length. The well-haired, tufted tail is at least
one-third the total length of the animal measuring 2 to 8 inches. Adult weight averages
between 0.5 and 3.0 ounces. The fur is usually soft and full with coloration varying with
habitat. For example, a lighter pelage is found in arid desert habitats, while grayish in cool
wood habitats. The ears are large relative to the rest of the body and are covered with fine
hairs.

Deer mice or White-footed mice are found in a great variety of habitats. The deer

mouse is widely distributed, but does not regularly occur in moist places. The white-footed
mouse also occurs over a large region but keeps mainly to deep woodlands or bushy areas.
Nests of the deer mouse are spheres of grass about 4 inches in diameter lined with down from

plants or with shredded materials. A soiled nest is abandoned, so several nests are built during
the year.

Food Habits

The diet of the white-footed and deer mouse includes seeds, nuts, berries, fruits,

insects and other small invertebrates, and carrion.

General Biology

Deer mice are largely nocturnal and active throughout the year, but they do experience

periods of torpor, involving a reduction in body temperature for several hours. They are
sociable mammals and in winter several mice may huddle together in a single nest.

The male mouse lives with the family and helps care for the immature young.

Breeding may occur throughout the year but most commonly March through October. Deer
and white-footed mice have a gestation period between 21 to 27 days and usually produce
three to four litters per year. The average litter size is about four young.

Damage Identification

A principal problem caused by white-footed and deer mice is their tendency to enter

homes, cabins, and other structures that are not rodent-proof. Once inside a structure, they
build nests, store food, and can cause damage to upholstered furniture, mattresses, clothing,
paper, or other materials that they find suitable for their nest-building activities. Nests,
droppings, and other signs left by these mice are similar to that of house mice. White-footed
and deer mice have a greater tendency to cache food supplies, such as acorns, seeds, or nuts,
than do house mice. They are uncommon in urban and suburban residential areas unless there
is considerable open space (fields, parks, etc.) nearby.

Both the white-footed mouse and deer mouse dig up and consume newly planted

seeds, flower beds, and field borders. Their excellent sense of smell makes them highly
efficient at locating and digging up buried seed. Formerly much reforestation was attempted
by direct seeding of clear-cut areas, but seed predation by the deer mice, white-footed mice
and other rodents and birds, caused frequent failure in the regeneration. For this reason, to re-
establish Douglas fir and other commercial timber species it is often necessary to hand plant
seedlings, despite the increased expense of this method.

This species of mice has been implicated as a major carrier of Hantavirus. Extreme

caution should be taken when implementing deer mouse control programs or cleaning up
debris or sites where these mice have frequented. Prior to beginning a clean-up or control
program, contact your local health department or county extension office.

Legal Status

White-footed and deer mice are considered native, non-game mammals and are

protected under Utah State law. They can be controlled when they are causing damage or
posing a public health threat.

Alternatives for Control

NON-LETHAL

Exclusion:

Rodent-proof construction is the best method of exclusion for mice.

All openings larger than 1/4 inch should be sealed with wire mesh 1/4 inch or
smaller. Fencing can be used to protect seeded garden plots. Bury the edges of
the wire several inches beneath the soil or prevent burrowing.

Cultural Methods:

Food items should be stored in rodent-proof containers.

All nesting opportunities and materials should be removed and fireplaces
sealed when not in use.

Frightening:

No effective methods are known to frighten Deer or white-footed mice.

Repellents:

Moth flakes or moth balls (naphthalene or paradichlorobenzene) may be
effective, but are not registered for repelling mice.

Live Traps

Automatic traps designed for live-capture are effective.

LETHAL

Toxicants:

Anticoagulant baits containing diphacinone, chlorophacinone, brodifacoum,
and bromadiolone are very effective. Brodifacoum and bromadiolone may be
effective in a single feeding.

Loose-grain bait formulations or secured paraffin wax bait blocks are also
effective.

Native to central Asia, this species arrived in North America along with European

settlers. The highly adaptable house mouse often lives in close association with humans and
therefore is termed one of the "commensal" rodents along with Norway and roof rats. House
mice are more common in residences and commercial structures than are rats. By gnawing,
climbing, jumping or swimming, house mice gain entry to structures.

Food Habits

The house mouse eats many types of food, but prefers seeds and grain. They will not

hesitate to sample new foods and are considered "nibblers." Foods high in fat, protein, or
sugar may be preferred even when grain and seeds are present. Such items include bacon,
chocolate candies, butter and nutmeats. A single mouse eats only about 1 ounce of food per
day (8 pounds per year), but because of their habit of nibbling on many foods and discarding
partially eaten items, mice destroy considerably more food than they consume.

Mice can get by with little or no water, although they readily drink water when it is

available. They obtain their water needs from the foods they eat. An absence of food or
adequate moisture content in their environment may reduce their breeding potential.

General Biology

House mice are mainly nocturnal, although at some locations considerable daytime

activity can be seen. Seeing mice during the daytime hours does not necessarily mean there is
a high population present, although this is usually true for rats.

Mice have poor eyesight, relying more on their hearing and their excellent senses of

smell, taste, and touch. They are also considered to be colorblind. Therefore, for safety
reasons, baits can be dyed distinctive colors without causing avoidance by mice, as long as
the dye does not have an objectionable taste or odor.

House mice can dig and may burrow into the ground in a field or around structures

when other shelter is not readily available. Nesting may occur in any sheltered location. Nests
are constructed of shredded fibrous material (paper, burlap, or similar items) and generally
have the appearance of a loosely woven "ball" of material. Nests are 4 to 6 inches in diameter.

Litters of 5 or 6 young are born 19 days after mating. Females can conceive while still

nursing. Mice are born naked and with their eyes closed. They grow rapidly and within 2
weeks are covered with hair and their eyes and ears are open. Young mice begin to make
short excursions from the nest and eat solid food at 3 weeks. Mice are sexually mature at 6 to
10 weeks. Mice may breed year-round, but when living outdoors are most actively
reproducing in spring and fall. A female may have up to 10 litters per year. Mouse
populations, can therefore, grow rapidly under ideal conditions. Breeding activities and the
survival of young decrease when population densities become high.