BLM California News.bytes 
News.bytes Extra, issue 559

The Ups and Downs of Bighorn Sheep Research

a bighorn sheep dangles in a sling beneath a helicopter
Peninsular Bighorn Sheep are airlifted to base camp for evaluation by an inter-agency research team to better understand threats facing this endangered species.  Photo:  BLM/S. Tyson

Peninsular Bighorn Sheep living in certain remote sections of Eastern San Diego and Western Imperial Counties were captured earlier this month in a joint agency research effort to better understand population dynamics and to determine -- and address -- threats to the population.  While captured, the bighorn sheep had their general health assessed, and were radio-collared so that scientists could track their movements and behaviors.  The sheep were released back into the area of their capture.

The BLM El Centro Field Office, the U.S. Border Patrol, the U.S. Fish & Wildlife Service and the California Department of Fish and Game worked together over 1 1/2 days to capture a total of 21 bighorn sheep.  The steep and remote terrain required that the sheep be located with a helicopter, and captured with a net fired from the aircraft at close range.  Once netted, biologists restrained the animals for airlift to a base camp where they could be physically examined and fitted with a radio collar. The sheep were then airlifted back to their area of capture, and immediately released.  The entire process, from capture to release, took approximately 60 minutes.  A veterinarian was on hand throughout the operation, to monitor and ensure the safety of the animal.  After release, all animals were active.

These 21 radio collared bighorn sheep will be tracked and monitored for potentially the rest of their lives.  Biologists hope the data they obtain will help with recovery efforts of this endangered species.  Scientists are interested in obtaining information about population status and trends, increasing their understanding of sheep movement between the U.S. and Mexico, determining the impact of roads as barriers, as well as the impacts of human activity on the species, and any diseases that may affect the population.  The BLM El Centro Field Office supports research of this kind to help sustain the ecological balance of the natural environment.

a group of people surround a restrained bighorn sheep
15 animals were captured on BLM non-wilderness public lands managed by the El Centro Field Office.  Here, the research team works quickly to examine and fit a collar to a captured animal.  Photo:  BLM/S. Tyson

researchers examine a hooded bighorn
A ewe is measured while blindfolded and hobbled.  Biologists minimized stress levels to the sheep by keeping capture-to-release times to an average of 60 minutes. Photo:  BLM/S. Tyson

BLM California News.bytes, issue 559 -- To subscribe to News.bytes, send an e-mail to: mailto:Join-Newsbytes@List.ca.blm.gov OR visit our News.bytes subscription page.