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PRYOR MOUNTAINS WILD HORSE RANGE
HERD MANAGEMENT PLAN
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(Information and images courtesy of BLM, Billings Resource Area Office)
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Preliminary Draft for Implementation
of the Pryor Mountain Wild Horse Range (PMWHR)
Herd Management Plan; July 1996
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GOAL#1 - PRESERVE PRYOR MOUNTAIN WILD HORSE ATTRIBUTES:
Maintain a healthy, viable herd of wild horses on the PMWHR, exhibiting
characteristics of historical value promoting heritage and wildness:
phenotypic attributes (color and conformation),
common
to existing Pryor Mountain horses, and including a diversity of body
colors and types typical of historical Spanish-type horses;
genotypic attributes (blood proteins and antigens),
common to existing Pryor Mountain horses, and maintaining sufficient
diversity to prevent the expression of recessive genes or other
potential inbreeding-related traits;
natural social order (harem bands and dominance
hierarchy), whereby critical and successful decision-making animals are
maintained as integral members to help preserve the natural working
integrity of the herd;
successful response to ecological pressures
(environmental, natural predators, humans), whereby animals
demonstrating a natural ability to retain flesh and health under stress,
produce healthy and viable foals, and demonstrate wariness towards
potentially harmful situations are maintained as integral parts of a
viable population.
DISCUSSION: The Pryor Mountain Wild Horse
Range presents a unique opportunity for the observation and study, or simple
viewing and appreciation of wild horses in a natural, diversified range
setting. In addition, the provisional history and genetic characteristics of
this population suggest early, Spanish-type ancestry. As such,
historically-significant features of these animals should be maintained both
to help promote our understanding and appreciation of wild horses, but also to
preserve these attributes for generations to come.
PLANNED ACTION: Based on earlier projections
of range carrying capacity, a minimum of 95 + 10% horses was
established (1992 Revised Herd Management Plan) as the appropriate management
level (AML) for the Pryor population. BLM is supporting current research
(National Biological Service) to determine a minimum genetically viable
population size for the Pryors, and compiling data on long-term population
recruitment following natural disasters (Table 1). Results of these research
efforts may suggest a future revision of the Herd Management Plan and
establish an allowable range for population numbers.
Resulting population size should allow for preservation of a near-natural
sex-ratio (50/50 to 60/40 in favor of females) and population age structure.
Natural processes (such as births and deaths), and population structure
(pertaining to social groups and mating choice), comprise the working
integrity of the herd and will be preserved as much as possible. In the
interests of successful and minimally-intrusive management, however,
immunocontraceptive techniques may be considered in the future (see goal
#3).
Accurate censusing (ground-truthing and aerial surveys) and identification
of all horses within the herd will take place on an annual basis. Due to the
level of effort necessary to accomplish this task, volunteer support from the
public and/or students will be sought out and highly encouraged. Currently,
an exemplary database (including photo-records of all possible horses), is in
the formative stages, compiling information from National Biological Service
researchers, BLM employees and volunteers and members of the local public.
Upon completion, copies of this database will be available from the Billings
Resource Area office upon request. Efforts are also being made to document
historical phenotype of these horses and members of the public with
photographs and/or information are invited to participate.
Four scientifically-based attributes (listed above) will be evaluated and
scored for each individual horse, and re-evaluated on an annual basis. In each
case, data will be invited and incorporated from scientific researchers with
expertise in each of these areas. Future genetic blood sampling, however,
will be restricted only to those animals being prepared and restrained for
adoption procedures. Selection lists, identifying potentially excisable
animals, will be developed in advance of culling efforts.
Opportunities will exist for fair public comment on culling choices. Given
the popularity of the Pryor horses for public adoption, culling criteria will
not emphasize desirability for adoption.
In order to solicit public participation in the long-term protection of the
Pryor horses, panels will be placed on several existing administrative signs,
during the summer of 1996, with the verbiage:
HELP PROTECT OUR WILD HORSES:
REPORT VIOLATIONS OF HARASSMENT,
INJURY, DEATH OR ILLEGAL REMOVAL
phone 406-238-1540
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With additional support from special interest groups, volunteers
and researchers, the BLM will continue to monitor public activity on the
Pryors, in an ongoing effort to balance management and/or law enforcement
visibility with critical use periods.
GOAL#2 - MAINTAIN A HEALTHY RANGE HABITAT:
Establish and maintain a healthy, viable range in balance
with the annual horse population and other wildlife. Given the multiple
purposes of the range, (primarily the protection and management of horses, but
also other wildlife, wilderness, watershed, recreation, etc), range
monitoring, will include, but may not be limited to:
horse migratory activity and seasonal range (actual) use,
to determine predictable patterns and identify areas of potential over
and/or under utilization by the horses. Other wildlife use will also be
incorporated into this analysis.
assessment of range health, in terms of vegetative quality
and quantity, with an emphasis on comparing and contrasting areas
representing different use levels by the horses.
evaluation of the need for range expansion efforts,
providing that additional acreage would be both available to and used by
the horses at appropriate times of the year. Evidence is needed that any
areas under consideration, must have been occupied by horses prior to
1971, in keeping with the Wild Free-Roaming Horse and Burro Act. These
efforts may be necessary to ensure sufficient range to support a
genetically viable population size.
DISCUSSION: Appropriate range monitoring
procedures and schedules are critical to permit sound management decisions
pertaining to range health within the PMWHR. Improved actual use,
utilization, and vegetative monitoring will enhance the current study site
database. Results and recommendations from current research efforts (Montana
State University and Colorado State University), should help facilitate a
sound risk-assessment approach. As much of the Pryor range encompasses
low precipitation zones featuring slow vegetative response, it is important
that all monitoring studies are designed for consistency and repeatability
over the long-term.
Horses on the PMWHR demonstrate the propensity to naturally segregate into
three geographically distinct herd areas - Burnt Timber Ridge, Sykes Ridge and
the Park Service Dryhead area. During some years, however, significant mixing
and sharing of mares and social groups may occur between different areas.
Although there is an estimated total of 38,014 acres available to the horses,
currently producing -1400 horse AUMS, Pryor horses demonstrate seasonal
activity which actually restricts optimal use of the entire available area.
Regular and recurrent monitoring will help elucidate activity and use patterns
particular to specific social groups of horses.
If range areas can be identified which the horses are consistently avoiding
or under-utilizing, this information must be incorporated into management
decisions. If range areas are identified which the horses are consistently
using on a trespass basis, then management must correct the situation or
consider range expansion efforts where feasible.
PLANNED ACTION: During the summer of 1996,
experienced BLM range conservationists, and National Biological Service and
university researchers, will be contacted to review and comment on proposed
monitoring programs. The long-term intent is to digitize this information
using a GIS database system. Efforts will also be initiated to document an
administrative history of the range with an emphasis on historical
distribution of horses in the Pryors and surrounding areas. Public assistance
is needed and encouraged with this documentation effort.
Actual Use: Actual use is determined by counting and
mapping presence of all social groups/horses on the range at various
times of the calendar year. From this data, key-use areas can be
identified, and the range can be stratified into seasonal use patterns.
Animal health, condition factors, and physiological condition will be
evaluated during this monitoring. In addition, fecal material can be
collected from targeted animals and social groups to evaluate
micro-histological composition and internal parasite count. Due to the
level of effort necessary to accomplish this task, volunteer support
from the public and/or students will be sought out and highly
encouraged.
Utilization: Vegetative 100-point utilization transects
(Key Forage Plant Method), with accompanying photographs, will be
performed within pre-determined key-use areas on a semi-annual schedule
(spring and fall). Grazing cages and enclosures will reveal the
productive potential of these areas under protected conditions as well
as grazing impact. These data will provide the most accurate
information regarding the degree of utilization and remaining available
forage in key areas. Throughout the field season, additional
utilization transects may also be performed at other points on the
range. This will help to identify possible horse preferences based on
environmental slope and aspect, and soil and forage type. This
information will help to elucidate and possibly explain under-utilized
range areas and forage.
Range Health: These studies will be conducted on pre
established sites located throughout the horse range. Evaluation of
Daubenmire plots will be replicated on a three to five year interval,
primarily during the early summer(May-June) field season. These efforts
will yield information on plant species lists and potential and current
plant productivity. There is long-term value in this type of study,
especially if efforts are consistent and repetitive over many (>20)
years
GOAL#3 - PROMOTE EFFECTIVE HERD MANAGEMENT STRATEGIES:
Target a strategy of humane (limited stress-inducing) and
minimum, cost-effective management in keeping with the 1971 Wild Free-Roaming
Horse and Burro Act. Emphasize a whole herd focus, wherein management
decisions prioritize long-term population viability, not necessarily
individual animal retention. Maintain a population number which:
ensures genetic viability of the population;
exists in balance with multiple uses and sustained
range health;
provides a suitable buffer against potential natural
disaster; and
provides sufficient animals to facilitate public
viewing.
DISCUSSION: The Pryor Mountain Wild Horse
Herd comprises a closed breeding system whereby additions to the population
are primarily the result of an annual foal crop. Different social groups,
within the population, can almost be predictably found in different areas of
the range corresponding with home range preferences and seasonal activities.
As a result, it is possible to concentrate culling activities on geographic
subsets of the range corresponding to patterns of use by selected horses.
This may permit successful removals of targeted horses without involving whole
population gathers which have been the historical management technique.
Subset gathers then, may involve: 1) bait- or water-trapping
efforts (depending on the targeted section of range), 2) helicopter
pressure into run-in traps located at various points throughout the range,
and/or 3) temporary and reversible immunocontraception of targeted
mares for foal crop reduction.
PLANNED ACTION: It is proposed, that with
careful monitoring programs, culling efforts can be established which consider
both the number of surviving foals from previous years and current
conditions of range health. This effort is designed to encourage
adaptability in management, generating long-term stability in available
resources and range health. Re-evaluation of management techniques and results
should take place at regular intervals.
BLM compiled data (Table 1) suggest an average annual foal crop of around
25-30 animals. Annual culling efforts should be maximized at this level. Once
selective culling lists have been developed and approved, and information is
available on migratory and use patterns of specific social groups, then gather
activities on geographic subsets of the range can take place.
Bait- or Water Trapping Efforts: Five bait and/or run-in
traps currently exist on the Pryor range. These traps are currently in
a state of disrepair and unusable. During the summer of 1996, BLM
personnel with long-term expertise in trapping efforts are being brought
in by the Billings Resource Area, to evaluate the design and
functionality of these traps. Placement of these traps, with respect to
designated wilderness areas, and accessibility for retrieval of captured
horses will also be an important consideration. Upon evaluation,
selected traps will be re-designed or re-vitalized to facilitate
successful, non- intrusive, limited stress-inducing trapping.
Subsequently (Sept/Oct 1996), contract professionals will be brought
in, via standard BLM bid procedure, to provide construction efforts on
the selected traps.
The Dryhead area, within the Bighorn National Recreational Area, will be
evaluated for water-trapping efforts, as well as helicopter run-in
gathers. Permission will be needed from the National Park Service in
order to construct possible temporary and/or permanent traps on this
part of the range.
Once the traps are ready for operation, a separate contract will be
activated to employ qualified professionals to provide trapping services
at designated traps and staggered time intervals. This timing must
consider targeted animals and their migratory and seasonal use patterns
of the range. Baiting may be in the form of hay, water or mineral
salts. Once trapped, targeted animals will be transported to holding
facilities at the Britton Springs Administration Site for preparation
for adoption. Remaining animals will be released directly from the trap
back onto the range. Initial trapping efforts may take place late fall
1996/early winter 1997 and resume summer 1997. Removal activities and
trapping efforts will not take place during foaling season (April 1
through June 30 inclusive).
Run-In Traps: The above bait traps will be evaluated and
designed for a dual function and purpose. Some social groups of horses
may never submit to bait trapping efforts and/or range resource
availability may nullify trapping success. If bait/water trapping
efforts are not successful, within an acceptable period of time, then it
is important that these same traps be available as run-in traps
involving helicopter efforts. The advantage to helicopter gathers is
that the work can be accomplished within a much shorter period of time,
reducing both management effort/costs and the potential risk of injury
to horses due to confinement.
Nationally-experienced, professional helicopter contractors for wild
horses, exist, who recognize the enhanced risk of danger within the
Pryor Mountain topography. It is possible to concentrate gathering by
helicopter on subsets of the range, facilitating removal of targeted
individuals, without subjecting the entire population to the stress of a
gather. In this effort, positioning of the traps and timing of the
effort would be such, that animals would not be pushed the entire length
of the mountain. This is an important consideration for animal safety
and well-being.
Immunocontraceptive Efforts: Immunocontraception is
currently not an approved management technique for the Pryor
horses. However, research on other populations, demonstrates a possible
one to three year contraceptive block as the result of injection with
the appropriate vaccine. The vaccine itself, produces no apparent
physiological side-effects or behavioral changes in the animals.
Evidence, to date, indicates that targeted animals continue to cycle and
are receptive to and bred by stallions. Targeted mares, captured in
traps, can be vaccinated and released without additional transport or
harassment. Once vaccinated the mares will develop levels of antigen
surrounding eggs in their ovary, which serve as a chemical block to
sperm penetration. After a few years, this process completely reverses
itself, such that the mare may once again conceive and produce a
foal.
The advantages to this process are three-fold. Individual animals may
stay on the range and live a natural lifestyle, without being subjected
to gathers, removals and the stress of domestication. Secondly,
targeted mares can again be reintroduced into the breeding cycle and
contribute to the gene pool. This can be an extremely critical
advantage when managing smaller, genetically restricted, breeding
populations like the Pryor horses. If the horses were removed from the
range, their future contribution to the gene pool would be lost forever.
Finally, with a decreased size in annual foal crop, management typically
becomes more cost-effective as intrusive removals are needed less
frequently. Removals will still be needed, perhaps once every five
years, with culled animals being available for adoption.
Immunocontraception could be available for limited trials with selected
Pryor mares as early as 1998. Public comment, consideration and
approval will be needed before BLM adopts this method as a management
strategy.
GOAL#4 - CONSTRUCT AND MAINTAIN AN EFFICIENT ADOPTION
FACILITY:
Activity within the Britton Springs Administrative Site will be limited
primarily to PMWHR management. It is necessary to remove the existing
corral facility, and construct a new. more simplified and efficient
system to the northeast of the spring area. The current facility exists
along the Britton Springs flow channel, and present surface run-off may,
during times of heavy use, carry animal waste into the Crooked Creek water
shed.
It is necessary to incorporate within the design, holding facilities which
will allow gathered animals to be held for a maximum of four weeks prior to
adoption. This is necessary in order to facilitate proper vaccination
schedules for the horses. All restraining and preparation activities at this
facility will be handled within a squeeze chute, except in rare situations
where a given animal is dangerously resistant to restraint by this method.
DISCUSSION: Long-term (10-20 years)
management projections indicate the decreasing need for whole population
gathers (>100 horses), with instead, an emphasis on geographic subset gathers.
The maximum required holding capacity of the corral system is estimated at
about 100 horses, with an average PMWHR effort involving approximately 30
horses. A facility of this size will also facilitate the occasional BLM
satellite preparation/adoption effort.
During times of confinement of Pryor Mountain horses, every effort will be
made to insure sound equine management techniques are being followed.
Particular attention will be given to animal health checks, consistent
provision of appropriate hay and water, cleanliness of the facilities,
appropriate use of veterinary services, and proper maintenance and supervision
of the facilities to insure safety of the horses, BLM employees and the
public.
PLANNED ACTION: Corral designs have been
prepared, reviewed extensively by a variety of both BLM internal and external
experts, and finalized (April 1996). These designs are on file and available
to the public through the BLM-Billings Resource Area. The designs include
separate holding pens for domestic horses used in PMWHR management
efforts.
Construction Efforts: The Navy SeaBees have
volunteered to assist with construction efforts, targeting two
weekends of effort - July 12/13/14 and August 2/3/4 1996. At the
completion of these weekends, the new facility should be near-completed
and the majority of the old structure should be demolished. Much of the
materials comprising the old corrals will be recycled and used in the
new facility. It is expected that the new facility will be fully
operational within a 2-3 month period following these efforts.
Reclamation of Britton Springs will be completed as soon as feasible
following completion of the new facility.
Maintenance Efforts: Prior to any scheduled gathers or
adoption efforts, a site safety inspection will be held. This will
permit facility repairs and improvements prior to housing any animals.
During times of confinement of horses within the holding facility,
consistent supervision will be provided by qualified BLM personnel
and/or fully-trained and approved BLM volunteers. During all
activities, detailed records will be kept, including but not limited to:
1) identification and health checks of each animal; 2) residency time of
each animal within the facility; 3) timing of vaccinations and
de-worming efforts; 4) need and use of professional veterinary services;
5) feeding, watering and corral cleaning schedules and checks; 6)
physical facility maintenance and repairs; 7) adoption administrative
activities.
Following each gather and adoption effort, the BLM will undergo a
self-evaluation process to help identify areas of management needing
improvement and to solicit ideas for successful implementation. The BLM
feels strongly that during the course of any culling or confinement
activities, the health, well-being and safety of horses, employees and
the public is equally paramount.
TABLE:
PRYOR MOUNTAIN WILD HORSE POPULATION DEMOGRAPHICS 1971-96
N/A indicates no available data
ALL data is approximate
ANNUAL COUNT = POSTFOALING AND POSTCULL
DATE | BIRTH RATE | DEATH
RATE | REMOVALS | ANNUAL COUNT | ADOPTED |
PRE-1971 | N/A | N/A | 60 | -200 | N/A
TD> |
1971 | N/A | N/A | 45 | -155 | 35 |
TR>
1973 | 11 | N/A | 35 | -120 | 35 |
1975 | 11 | 15 | 25 | -140 | 25 |
1977 | 26 | 0 | 25 | -145 | 25 |
1978 | 15 | -72 | 0 | -87 | 0 |
1979 | 23 | 5 | 0 | 105 | 0 |
1980 | 27 | 7 | 1 | 127 | 1 |
1981 | 35 | 1 | 6 | 155 | 6 |
1982 | 35 | 3 | 43 | 144 | 43 |
1983 | 30 | 6 | 21 | 147 | 21 |
1984 | 25 | 18 | 13 | 141 | 13 |
1985 | 25 | 2 | 25 | 139 | 25 |
1986 | 29 | 13 | 0 | 155 | 0 |
1987 | 32 | 17 | 23 | 147 | 23 |
1988 | 26 | 17 | 26 | 130 | 26 |
1989 | 20 | 12 | 21 | 122 | 21 |
1990 | 32 | N/A | 3 | 133 | 3 |
1991 | 28 | 5 | 16 | 120 | 16 |
1992 | 38 | N/A | 46 | 115 | 46 |
1993 | 22 | N/A | 1 | 143 | 1 |
1994 | 34 | 3 | 51 | 118 | 51 |
1995 | 28 | 0 | 0 | 146 | 0 |
1996 | 29 | 5 | 0 | 175 | 0 |
Please Note:
This is not a BLM operated or BLM sponsored site. It
is run by private wild horse and burro enthusiasts. We are thankful to the
BLM for providing the information which is presented here. We also hope to
soon be posting information pertaining to HMAs in other states.
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