GARY L. NUNLEY, U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Texas
Animal Damage Control Service, P.O. Box 100410, San
Antonio, TX 78201-1710
Abstract: A variety of control methods used over an 80-year period (1915-1995) contributed to the effective
and successful coyote (Canis latrans) damage management program that exists in Texas today. Traps,
toxicants, shooting, denning, and dogs were important during the early years of the Texas Animal Damage
Control Service (TADCS) program. Aerial hunting and snares evolved as important control tools following
the ban on strychnine and Compound 1080 in 1972. The livestock protection collar (LPC) has received
increased use in recent years and has been useful in resolving difficult depredation problems. ADC policy
along with changing state and federal regulations and public opinion will dictate how specific control tools
are used in the future.
Texas leads the nation in the production of
domestic sheep and goats. Although the total
number of these livestock has declined in recent
years, there were 1,700,000 sheep and 1,950,000
goats present in the state during 1995 (USDA
1995) (Fig. 1). The Edwards Plateau and
adjoining ecological areas contain the highest
concentration of both species (Fig. 2).
Organized predator control sponsored by the
U.S. Bureau of Biological Survey began in Texas
with the hiring of 8 hunters in November 1915.
Their work was concentrated in the sheep
producing areas of the Edwards Plateau and
expanded to other areas in later years (Nunley
1986). Traps, shooting, and strychnine baits were
the primary control tools used. As the sheep
industry expanded, so did federal and state
government efforts to protect livestock producers.
Today there are 142 employees involved in coyote
predation control efforts in 140 of the 254
counties in Texas.
This paper describes the history of coyote
control as conducted by the TADCS since the
beginning of the program. Primary emphasis is
given to the period from 1972 to the present. We
also evaluate how public attitudes and political
events have influenced the use of control tools in
the past and how they may influence the use of
tools in the future.
Coyote control methods
Perhaps no other area of the United States
(U.S.) can boast of a more effective and successful
coyote predation control program than the
Edwards Plateau region of Texas. This area has
been under intensive predator management since
at least1915. The use of a variety of control tools
eventually led to the extirpation of coyotes, red
wolves (C. rufus), and gray wolves (C. lupus) from
the major sheep production areas. Exactly how
this task was accomplished is unknown, but
Shelton and Klindt (1974) suggested that it
resulted from a "massive human effort using all of
the tools and techniques which could be brought
to bear."
By the early 1920s, all red wolves and nearly
all coyotes were eliminated from the interior sheep
and goat producing counties of the Edwards
Plateau (Nunley 1986). It wasn't until the 1970s
that coyotes began to re-establish; red wolves have
not reinvaded the area.
Over the years many control tools have been
used, including toxicants, shooting, aerial
hunting, calling, dogs, traps, cyanide ejectors,
snares, denning, and more recently the LPC. A
historical review of each major control method is
provided below.
Toxic baits. Strychnine placed in meat and
tallow baits was widely distributed in all sheep-
and goat-raising areas when organized control
efforts began in 1915. No records on the number
of baits used are available for the early years, but
in FY 1950, over 182,000 baits were used to
reduce coyote populations. In FY 1960, over
328,000 baits were distributed, and by 1971 this
number had increased to 408,000. Undoubtedly,
strychnine played a major role in suppressing
coyote numbers in buffer areas and reduced the
possibility of reinvasion into major sheep and goat
raising areas.
Compound 1080 was first used in Texas in
1949. Like the rest of the West, large meat baits
were treated and placed in strategic locations
during the winter months. During the peak of
1080 use in the 1960s, approximately 1,000 baits
per year were used (Fig. 3). Compound 1080 was
used in all regions of the state except east Texas,
but most frequently in the counties adjacent to the
Edwards Plateau and Panhandle regions. The use
of 1080 and strychnine ceased in 1972 following
Executive Order 11643 and the cancellation of
predacides by the Environmental Protection
Agency (EPA).
Traps. Steel foothold traps were an important
tool when organized wolf and coyote control
efforts began. The No. 4 Newhouse has been the
trap of choice by Texas trappers since the program
first started purchasing traps. The TADCS has
over 9,000 traps in its inventory today and 86%
are No 3½ or 4 Newhouse. ADC field personnel
relied heavily on traps following the cessation of
1080, strychnine, and M-44 cyanide ejector use.
In FY 1973, TADCS personnel used traps to take
10,058 coyotes which represented 67% of the
coyotes taken by all control methods. By
comparison, in 1994, only 1,666 coyotes were
taken in traps; this equaled 8% of the coyotes
taken by all methods (Fig. 4).
A similar pattern showing the declining use
of traps is prevalent in many other western ADC
programs. The reduced use of traps has come
about for several reasons. Perhaps the most
significant is the increased effectiveness and use
of the M-44 device which became available for
experimental use in 1974, and was subsequently
improved substantially and reregistered. Traps
will continue to be an important tool in coyote
control, but with availability of other less labor
intensive methods, they will not receive the use
they have in the past.
Snares. Although snares were always available as
a control tool, they were not widely used in the
TADCS program until 1959. As woven ("net")
wire fences became more common in sheep and
goat producing areas, the potential effectiveness of
snares as a "first line of defense" against coyotes
invading pasture was recognized.
Snares are typically set in "crawl holes" under
fences. The most common fence snare used by
TADCS personnel is about 34 inches (86 cm) in
length and constructed with 5/64 inch (2.0 mm)
diameter aircraft cable using a "sure lock". By
1972, snares were responsible for taking 1,576
coyotes. Their use has expanded since then and in
1994, snares were used to capture 5,879 coyotes or
28% of the coyotes taken by all control methods
(Fig. 5). Guthery and Beasom (1978) working in
South Texas reported that neck snares were about
12 times more selective than leghold traps for
capturing predatory mammals.
Aerial hunting. Although aerial hunting with
fixed-wing aircraft and helicopters was used prior
to 1972, this control method was not common
until toxicant uses were canceled. Both fixed-wing aircraft and helicopters are used in the Texas
program. Fixed-wing aircraft are typically used in
the more rolling and open areas of the Trans-Pecos, Panhandle, and the western portion of the
Edwards Plateau while helicopters are used in the
rougher terrain around the Edwards Plateau.
The TADCS program currently owns 1
helicopter and 2 fixed-wing aircraft. Two
helicopters are used on a contractual basis. These
aircraft are used in all areas of the state (except
east Texas) as specific needs occur. The number
of coyotes taken by aircraft peaked in 1975 with
5,983 animals taken that year. Since 1982, there
has been a gradual increase in the number of
coyotes taken each year by aircraft with 3,692
taken in 1994 (Fig. 6).
Coyote-getters/M-44 devices. The Coyote-Getter,
a primer-powered cyanide ejector using a sealed
.38 special casing, was widely used in Texas after
it was introduced into governmental predator
control around 1940. Young and Jackson (1951)
reported that in October 1946, A. B. Bynum, a
TADCS employee took 536 coyotes using 325
"getters" in Maverick County. The coyote getter
proved to be an effective control tool for the next
30 years and was widely used by TADCS
personnel. For example, in FY 1960, 21,526
coyotes were taken by "getters" in the Texas
program.
After years of development and testing, the
M-44 device cyanide ejector officially replaced
coyote getters in the ADC program (Bacus, 1969,
n.d.). M-44s were immediately used in the Texas
ADC program and in 1972 were responsible for
taking 7,567 coyotes. Use of this tool was
suspended following the EPA cancellation of all
predacide registrations in 1972. Use was resumed
under experimental permits in 1974. Registration
by EPA occurred in 1975 and reregistration under
the new guidelines, in 1994.
Despite early mechanical problems with
ejectors and sealants, there has been a progressive
increase in M-44 use since 1975. The highest
number of coyotes taken with this device was
8,250 in 1993 (Fig. 7). M-44s receive their
greatest use during the winter months but can be
effective during all times of the year.
During the period 1976-86, more coyotes
were taken by M-44s in Texas than in all other
states combined. Connolly (1988) attributed this
to the following reasons: (1) the Texas ADC
program is much larger than the others; (2) most
Texas grazing lands are in private ownership,
which is appropriate for M-44 use; (3) dense
vegetation in many areas of Texas precludes
effective aerial hunting, which is a primary
technique in most other states; and (4) much
control work in Texas is done in livestock
pastures, where livestock interfere less with M-44s
than with steel trap sets.
Livestock Protection Collar. The Livestock
Protection Collar (LPC) was invented by Roy
McBride as a method to take "problem coyotes"
that were difficult to take with conventional
control tools. The LPC is the most selective and
specific of all control tools because it removes
only the individual animal responsible for killing
livestock. Although 5 states have established
programs to use the LPCs, only Texas has made
substantial use of this new control tool. The LPC
has been used by state-certified rancher
applicators since 1988 and by ADC field
personnel since 1990.
Connolly (1993) summarized use of the collar
by the TADCS program for the period FY 1990 -
1992. He reported 2,348 collars were placed on
livestock which resulted in 46 being punctured by
coyotes. J. Dorsett, TADCS District Supervisor
(pers. commun.) reported that since 1992, an
additional 3,196 collars were placed on livestock
resulting in 63 coyote punctures.
Nonlethal control methods
Texas sheep and goat producers have used a
variety of nonlethal techniques to protect their
livestock from coyote predation. When sheep
were first established on the Edwards Plateau,
herders were used extensively to guard sheep. In
the 1920s, a major effort was made to fence
individual ranches into large pastures with woven
wire fences. Many of the fences were equipped
with wire aprons to make them "predator proof".
The elaborate fence network on the Edwards
Plateau probably contributed more than any other
factor to reducing or, in many cases, eliminating
predator losses.
In recent years, many livestock producers
have experimented with different types of
guarding animals to protect their flocks. One of
the most popular techniques has been the use of
guard dogs such as the Great Pyrenees, Komodor,
and Akbash breeds. In 1993, TADCS estimated
that 5 to 10% of the sheep and goat producers
were using guard dogs. The use of guard donkeys
has also increased in popularity in recent years.
Walton and Feild (1990) estimated that
approximately 9% of the sheep and goat producers
were using donkeys in 1989. Most of the donkeys
being used are single jennies or geldings.
The TADCS and Texas Department of
Agriculture advocate and promote the use of
nonlethal techniques to reduce conflicts between
predators and livestock producers. In 1994, Texas
ranchers spent an average of $0.51 per head
(breeding ewe) annually on nonlethal predator
control measures (USDA 1995). This effort will
most likely continue in the future.
Public opinion and coyote control methods
A historical review of the use of coyote
control methods has demonstrated the importance
of public opinion in dictating the availability of
specific tools. During the early years of predator
control in the West, there was public support for
removal and elimination of large predators such as
wolves and coyotes. This was because a large
percentage of the American public lived on the
land or had a close association with relatives that
made their living from farming or ranching. The
movement of people from rural environments to
urban areas in the past 50 years has brought about
substantial change in public attitudes towards
predator control.
The most significant events that brought
immediate changes to the use of coyote control
methods were the Cain Committee Report (Cain
et al. 1972) and the cancellation of predacide
registrations by EPA. Toxicants were important
in the TADCS program and were very effective in
suppressing coyote predation in many areas of the
state. The use of Compound 1080 bait stations
was believed to be extremely effective in reducing
coyote numbers on the fringe areas of the Edwards
Plateau.
Despite the lack of 1080 and strychnine baits
over the past 23 years, the TADCS has been able
to minimize predator losses by shifting to and
improving the use of other control methods.
Aerial hunting, although more costly and
hazardous to ADC personnel, has been effective in
removing coyotes from many problem areas.
Improvements in the use of snares and M-44s
have been helpful in resolving depredation
problems. Lastly, the LPC has proved effective in
removing coyotes that were difficult to take with
other methods.
Public sentiment against the use of foothold
traps to capture animals has increased in recent
years (Gentile 1987). An effort is underway
through the International Organization for
Standardization (ISO) to develop an international
standard with criteria for the humane use of traps
for capturing particular species (Jotham and
Phillips 1994). Recent testing of several types of
traps suggests that only padded jaw traps among
the traps currently in use would meet proposed
criteria for capturing coyotes with minimal injury.
The future of the ISO standards is unknown at this
time; however, some type of national or
international standard, reflected in state laws,
appears likely in the next few years.
Within the past 2 years, 2 western states
(Arizona and Colorado) have made major changes
that affect how traps can be used for capturing
coyotes. Arizona currently prohibits all trapping
on public lands. Colorado has passed regulations
which allow only padded traps to be used in land
sets. Because most of the land in Texas is under
private ownership it appears unlikely that such
changes affecting the use of traps for predator
control in Texas will occur in the near future. We
expect all current tools for managing coyote
predation will continue to be used in Texas into
the foreseeable future and that some new
techniques will become available.
Acknowledgements: We thank K. Gruver for his
assistance in compiling historical data from the
TADCS annual reports and G. Connolly for
contributing ideas and numerous unpublished
materials which were useful in preparing this
paper. M. Fall and G. Connolly kindly reviewed
the manuscript and provided helpful suggestions.
K. Flynn prepared most of the figures and typed
the paper.
Literature Cited
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Figure 1. Trends in sheep and goat numbers in Texas (1920-95).
Figure 2. Distribution of sheep and goats in Texas (Texas Crop and Livestock Reporting Service 1994).
Figure 3. Numbers of 1080 baits placed in Texas (1950-1972).
Figure 4. Trends in the number of coyotes taken in foothold traps by TADCS (1972-1994).
Figure 5. Trends in the number of coyotes taken in snares by TADCS (1972-1994).
Figure 6. Trends in the number of coyotes taken by aerial hunting by TADCS (1972-1994).
Figure 7. Trends in the number of coyotes taken by M-44s by TADCS (1972-1994).
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