Terms and Definitions
Wild
An animal that is untamed or undomesticated in a natural state; originating from ancestors that have never been domesticated or modified by selective breeding.
Feral
An animal or plant is considered feral if the population was once domesticated but has subsequently either escaped human captivity, strayed, or has purposefully been released or abandoned.
Wild Free-Roaming Horses and Burros
(As defined in the Act) “All unbranded and unclaimed horses and burros on public lands of the United States.”
Free-Roaming
Unbranded and unclaimed animals that are to be managed within the territory legally established by the Act.
Range
(As defined in the Act) “The amount of land necessary to sustain an existing herd or herds of wild free-roaming horses and burros, which does not exceed their known territorial limits, and which is devoted principally but not necessarily exclusively to their welfare in keeping with the multiple-use management concept for the public lands.”
Herd
(As defined in the Act) “One or more stallions and his mares.”
Public Lands
“Any lands administered by the Secretary of the Interior through the Bureau of Land Management or by the Secretary of Agriculture through the Forest Service.”
Herd Area
The areas in which “wild” horses and burros were found in 1971. These are the only areas BLM may manage horses by law.
Herd Management Areas (HMA)
The areas within each Herd Area that was evaluated by BLM to have adequate food, water, cover, and space to sustain healthy and diverse “wild” horse and burro populations over the long term. These were calculated using GIS.
Appropriate Management Level (AML)
The number of “wild” horses and burros that the BLM determines can exist in balance with other public rangeland species, resources, and uses in a given area. AML represents the point at which horse and burro herd populations are consistent with the land’s capacity to support them. The AML is a range of low to maximum levels that allows for population growth over a four- to five-year period without causing rangeland damage. The appropriate AML is established once it is determined that the essential habitat components are present in sufficient amounts to sustain healthy horse and burro populations and healthy rangelands over the long-term, the amount of sustainable forage available for horse and burro use is determined, and it is determined whether or not the project herd size is sufficient to maintain genetically diverse horse and burro populations. The U.S. AML determined by BLM is approximately 26,500. The current “free-roaming” population exceeds this by about 11,000.
Animal Unit Month (AUM)
The carrying capacity of the land to support grazing animals such as horses, burros, cattle, and sheep. The AUM is calculated based on species, weight, and presence of a juvenile. BLM generally considers a “wild” horse one year of age or older as 1 AU, and burros one year of age or older as 0.5 AU. An animal unit is commonly defined as 1,000 pounds of body weight and an AUM is the amount of forage needed to sustain an AU for one month. The AUM for an HMA is used to determine the AML for the area.
Wild Free-Roaming Horses and Burros Act
Federal legislation enacted in 1971 that aims to protect “wild, free-roaming” horses and burros from capture, branding, harassment, or death. This act guides management of “wild” horses and burros as an integral part of the natural system on Bureau of Land Management (BLM) and U.S. Forest Service lands in the western United States. The Act gives responsibility of management to BLM and the Forest Service, and requires the Secretary of the Interior and the Secretary of Agriculture to protect and manage these animals as components of the public lands and maintain ecological balance on the principle of multiple-use. The Secretaries are also responsible for maintaining a current inventory of the animals on these lands to determine if and where overpopulation problems exist and what, if any, actions should be taken to remove excess animals. The 1971 Act was later amended by the Federal Land Policy and Management Act (FLPMA) of 1976 and the Public Rangelands Improvement Act of 1978.
Federal Land Policy and Management Act (FLPMA, Public Law 94-579)
An act written to “establish public land policy, to establish guidelines for its administration, [and] to provide for the management, protection, development, and enhancement of the public lands.” It allowed for the Secretaries of the Interior and Agriculture to use or contract for the use of helicopters and motorized vehicles for the purpose of managing “free-roaming” horses and burros on public lands.
The Public Rangelands Improvement Act (Public Law 95-514)
An act to establish or reaffirm the need of inventory and identification of current public rangeland conditions and the management, maintenance, and improvement of public rangeland conditions to support all values the rangeland offers. It established the continuance of provisions protecting the animals from capture, branding, harassment, or death while facilitating the removal of excess horses and burros, and the transfer of the title of ownership after one year to individuals that adequately and humanely cared for their adopted horses and burros that were removed from public rangelands.
An animal that is untamed or undomesticated in a natural state; originating from ancestors that have never been domesticated or modified by selective breeding.
Feral
An animal or plant is considered feral if the population was once domesticated but has subsequently either escaped human captivity, strayed, or has purposefully been released or abandoned.
Wild Free-Roaming Horses and Burros
(As defined in the Act) “All unbranded and unclaimed horses and burros on public lands of the United States.”
Free-Roaming
Unbranded and unclaimed animals that are to be managed within the territory legally established by the Act.
Range
(As defined in the Act) “The amount of land necessary to sustain an existing herd or herds of wild free-roaming horses and burros, which does not exceed their known territorial limits, and which is devoted principally but not necessarily exclusively to their welfare in keeping with the multiple-use management concept for the public lands.”
Herd
(As defined in the Act) “One or more stallions and his mares.”
Public Lands
“Any lands administered by the Secretary of the Interior through the Bureau of Land Management or by the Secretary of Agriculture through the Forest Service.”
Herd Area
The areas in which “wild” horses and burros were found in 1971. These are the only areas BLM may manage horses by law.
Herd Management Areas (HMA)
The areas within each Herd Area that was evaluated by BLM to have adequate food, water, cover, and space to sustain healthy and diverse “wild” horse and burro populations over the long term. These were calculated using GIS.
Appropriate Management Level (AML)
The number of “wild” horses and burros that the BLM determines can exist in balance with other public rangeland species, resources, and uses in a given area. AML represents the point at which horse and burro herd populations are consistent with the land’s capacity to support them. The AML is a range of low to maximum levels that allows for population growth over a four- to five-year period without causing rangeland damage. The appropriate AML is established once it is determined that the essential habitat components are present in sufficient amounts to sustain healthy horse and burro populations and healthy rangelands over the long-term, the amount of sustainable forage available for horse and burro use is determined, and it is determined whether or not the project herd size is sufficient to maintain genetically diverse horse and burro populations. The U.S. AML determined by BLM is approximately 26,500. The current “free-roaming” population exceeds this by about 11,000.
Animal Unit Month (AUM)
The carrying capacity of the land to support grazing animals such as horses, burros, cattle, and sheep. The AUM is calculated based on species, weight, and presence of a juvenile. BLM generally considers a “wild” horse one year of age or older as 1 AU, and burros one year of age or older as 0.5 AU. An animal unit is commonly defined as 1,000 pounds of body weight and an AUM is the amount of forage needed to sustain an AU for one month. The AUM for an HMA is used to determine the AML for the area.
Wild Free-Roaming Horses and Burros Act
Federal legislation enacted in 1971 that aims to protect “wild, free-roaming” horses and burros from capture, branding, harassment, or death. This act guides management of “wild” horses and burros as an integral part of the natural system on Bureau of Land Management (BLM) and U.S. Forest Service lands in the western United States. The Act gives responsibility of management to BLM and the Forest Service, and requires the Secretary of the Interior and the Secretary of Agriculture to protect and manage these animals as components of the public lands and maintain ecological balance on the principle of multiple-use. The Secretaries are also responsible for maintaining a current inventory of the animals on these lands to determine if and where overpopulation problems exist and what, if any, actions should be taken to remove excess animals. The 1971 Act was later amended by the Federal Land Policy and Management Act (FLPMA) of 1976 and the Public Rangelands Improvement Act of 1978.
Federal Land Policy and Management Act (FLPMA, Public Law 94-579)
An act written to “establish public land policy, to establish guidelines for its administration, [and] to provide for the management, protection, development, and enhancement of the public lands.” It allowed for the Secretaries of the Interior and Agriculture to use or contract for the use of helicopters and motorized vehicles for the purpose of managing “free-roaming” horses and burros on public lands.
The Public Rangelands Improvement Act (Public Law 95-514)
An act to establish or reaffirm the need of inventory and identification of current public rangeland conditions and the management, maintenance, and improvement of public rangeland conditions to support all values the rangeland offers. It established the continuance of provisions protecting the animals from capture, branding, harassment, or death while facilitating the removal of excess horses and burros, and the transfer of the title of ownership after one year to individuals that adequately and humanely cared for their adopted horses and burros that were removed from public rangelands.