Skip to Content


Limiting Mountain Lion Predation on Desert Bighorn Sheep on Kofa National Wildlife Refuge, Yuma and La Paz Counties, AZ

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Fish and Wildlife Service, Interior.


Notice of availability of the final environmental assessment and a finding of no significant impact.


We, the U.S. Fish and Wildlife Service (Service), announce availability of our finding of no significant impact (FONSI) for the environmental assessment (EA) for limiting mountain lion (Puma concolor) predation on desert bighorn sheep (Ovis canadensis mexicana) on the Kofa National Wildlife Refuge (Refuge) in southwest Arizona. In the final EA and FONSI, we describe how we will manage mountain lion predation to help achieve bighorn sheep population objectives on the Refuge.


You may view or obtain copies of the FONSI and final EA by the following methods. You may request a hard copy or CD-ROM by U.S. mail from U.S. Fish and Wildlife Service, 9300 East 28th Street, Yuma, AZ 85365; via facsimile at 928-783-8611; or electronically to You may also download a copy of the documents at:​southwest/​refuges/​arizona/​kofa.

Start Further Info


Mitch Ellis, 928-783-7861 (phone); 928-783-8611 (fax); or (e-mail). If you use a telecommunications device for the deaf (TDD), you may call the Federal Information Relay Service (FIRS) at 1-800-877-8339, 24 hours a day, 7 days a week.

End Further Info End Preamble Start Supplemental Information



With this notice, we announce our decision and the availability of the FONSI and final EA. We completed a thorough analysis of impacts on the human environment, which we include in the final EA that accompanies the FONSI. We solicited comments on a draft EA from August 4, 2009, to October 2, 2009, through a notice of availability in the Federal Register (74 FR 38667; August 4, 2009). We received 220 responses during the comment period, from 7 government agencies, 19 nongovernmental organizations, and 194 individuals. During preparation of the final EA, we considered all of the comments provided. Appendix C of the final EA contains a more detailed description of the substantive comments received and how we incorporated changes to the draft EA in response to comments we received.


The Refuge contains a major portion of the largest contiguous habitat for desert bighorn sheep in southwestern Arizona and historically has been home to a population averaging 760 bighorns. The Refuge has served as the primary source of bighorn sheep for translocations to reestablish and supplement extirpated or declining populations throughout southern Arizona, New Mexico, Texas, and Colorado. Population estimates from systematic aerial surveys indicate that a 50-percent decline in the Refuge sheep population occurred between the years 2000 and 2006.

In response to this decline, the Refuge and the Arizona Game and Fish Department (AGFD) have conducted an analysis of its probable causes and are currently implementing a strategic management program intended to lead to the recovery of this important wildlife resource. Several studies and monitoring projects have been initiated or enhanced. Some of the more important aspects of this broad program include more frequent bighorn population surveys, monitoring and maintaining water availability, assessing body condition and disease in the bighorn population, monitoring disturbance attributable to human recreation, and monitoring the extent of predation and its impacts on the population. Many of the elements in this management program have been addressed through prior planning documents and require little additional review. Others, such as the proposed lethal control of mountain lions, have not been previously addressed and therefore require analysis under the National Environmental Policy Act of 1969, as amended (NEPA; 42 U.S.C. 4321 et seq.), as well as public review.

Final Environmental Assessment—Selected Alternative

The final EA identifies and evaluates three alternatives for managing mountain lion predation on desert bighorn sheep on the Refuge. After a thorough analysis, we have selected Alternative B for implementation. Under this alternative, we will allow the removal of specific, individually identified offending mountain lions, through translocation or lethal removal, from the Refuge under certain circumstances, in order to recover and maintain an optimal population of desert bighorn sheep. This program has several components. We will trap mountain lions and fit them with tracking devices to monitor their activities. When the Refuge bighorn sheep population estimate is below 600 animals, active mountain lion control will occur. Active mountain lion control is the removal (through lethal means or translocation) of each individual mountain lion found to kill two or more bighorn sheep within a 6-month period. The Service, or its agents, will carry out the lethal removal or translocation. However, when the Refuge bighorn sheep population estimate is between 600 and 800 animals, active mountain lion control may or may not be Start Printed Page 28643employed based on the totality of the circumstances at the time. In order to meet the bighorn sheep population objectives while minimizing the necessary impacts to mountain lions, we desire some flexibility. We will base decisions regarding whether active mountain lion control is necessary on an adaptive management approach and on the following factors: The current sheep population estimate; the current sheep population trend; bighorn sheep lamb survival and recruitment; the estimate of the number of mountain lions currently using the Refuge and their predation rate on bighorn sheep; current and forecasted habitat conditions; available funding and manpower; and criticality of bighorn translocation needs. When the Refuge bighorn sheep population estimate is at or above 800 animals, active mountain lion control will not occur, although mountain lions on the Refuge will continue to be captured and fitted with tracking devices to aid in continuing research.

Additional Refuge Information

Additional information on the history of the Refuge and its purpose, goals, objectives, and management strategies can be found in the Kofa National Wildlife Refuge & Wilderness and New Water Mountains Wilderness Interagency Management Plan and Environmental Assessment: EA-AZ-055-95-1 05, October 1997. Pertinent information can also be found in the April 2007 report titled Investigative Report and Recommendations for the Kofa Bighorn Sheep Herd, prepared jointly by the Service and the AGFD. Both documents, along with other detailed information, are available at the following web site:​southwest/​refuges/​arizona/​kofa.


Environmental review of this project has been conducted in accordance with the requirements of NEPA, NEPA Regulations (40 CFR parts 1500-1508), other appropriate Federal laws and regulations, Executive Order 12996, the National Wildlife Refuge System Improvement Act of 1997, and Service policies and procedures for compliance with those laws and regulations.

Start Signature

Dated: December 18, 2009

Benjamin N. Tuggle,

Regional Director, Region 2.

End Signature End Supplemental Information

[FR Doc. 2010-12247 Filed 5-20-10; 8:45 am]