Background: Wild Burro populations on BLM lands exceed allowable management levels (AML) in the majority of herd management areas (HMA) where wild burros are found. It is not feasible to remove the excess wild burros because of the high costs of such removals and the attendant costs of adoption and long-term holding. One management strategy that BLM has prioritized is to reduce burro population growth on the range. Immunizing horses and burros with porcine zona pellucida (PZP) leads to an immunological reaction such that treated animals have lower fertility. Treatment with PZP requires an initial dose, and a booster dose at least two weeks after the initial dose. Ideally, PZP is then boostered annually to achieve contraception for the year following booster application. The BLM has received a proposal from the Humane Society of the United States (HSUS) to initiate an adaptive management project involving PZP in the vicinity of Oatman, Arizona, where burro populations are high and where some burros are habituated to proximity with people. With the BLM's collaboration, the partner will be trapping, handling, marking, treating burros with PZP, and then monitoring the foaling outcomes for treated and untreated female burros. Note: Although the BLM has been in discussions with the Humane Society of the United States regarding this unsolicited proposal and intends to financially assist them with this project, other applicants are invited to submit proposals for consideration. The HSUS and other partners will be required to bring a substantial (3:1, Partner:BLM) cost-sharing commitment to the project. Objectives: Through financial assistance, the BLM seeks to support and foster an adaptive management project demonstrating the use of PZP on habituated and non-habituated wild burros, where there will be close monitoring of results, and where there may be potential lessons for subsequent management elsewhere. Specific objectives of the desired project are to treat approximately 20 habituated female burros in the vicinity of Oatman, AZ, with PZP and to treat approximately 75 or more non-habituated female burros in the surrounding areas with PZP, with boostering via darting in some cases and in hand in other cases; to document effort required to effect that treatment; and to monitor the foaling rate outcomes of treated and non-treated female burros. Public Benefit: Wild burros in the vicinity of Oatman, Arizona, attract tourists to the town and are a notable public benefit. At the same time, burros can pose a hazard to vehicle drivers in the area. A demonstration project that uses the PZP contraceptive agent to reduce burro population growth in this geographic area would be of value to the public by stabilizing the number of burros present in the area to a number that is manageable as a tourist draw and prevent damage local natural resources. Having a well-known demonstration project will entice more tourism in the area in order to see individually-recognizable burros and learn more about burro ecology and management. Assisting and supporting such a project will also be of value as an example of wild burro population growth suppression which can inform wild burro management in other areas.