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CARLSBAD FWO: Endangered Sheep Get the Collar
California-Nevada Offices , May 13, 2014
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A helicopter transports an endangered bighorn sheep as part of radio-collaring effort to learn more about the species and its behavior.
A helicopter transports an endangered bighorn sheep as part of radio-collaring effort to learn more about the species and its behavior. - Photo Credit: USFWS
Carlsbad FWO biologist Patrick Gower works with CDFW, BLM and Customs and Border Patrol personnel to examine and radio-collar a bighorn sheep.
Carlsbad FWO biologist Patrick Gower works with CDFW, BLM and Customs and Border Patrol personnel to examine and radio-collar a bighorn sheep. - Photo Credit: USFWS
Ewe wearing a radio-collar forages in Anza Borrego Desert State Park.
Ewe wearing a radio-collar forages in Anza Borrego Desert State Park. - Photo Credit: USFWS

By Patrick Gower

The whoosh of rotor-blades and a whirlwind of dust fills the air as a small red helicopter with a bundle slung underneath, comes to a hovering stop over a bare patch of California desert, close to the Jacumba Mountains Wilderness. With a tenderness that amazes all onlookers, the helicopter pilot gently places the bundle upon the ground. Once the bundle is unhooked, the helicopter quickly buzzes away. A group of biologists and veterinarians from the U.S. Fish and Wildlife Service (Service), California Department of Fish and Wildlife (CDFW) and the Bureau of Land Management (BLM) - 'the processing team'- rush forward and hustle the bundle into the shade at a processing station located nearby. Once in the shade, the bundle is unwrapped revealing a federally endangered adult Peninsular bighorn sheep ewe neatly hobbled and blindfolded, ready for processing and collaring.

The processing team works quickly. First dousing her with water to keep her cool, the team performs an examination and sampling protocol that includes looking for obvious signs of injury or illness, and collecting samples of blood, hair, nasal mucous and fecal pellets. Finally, the ewe is fitted with a radio collar and GPS pod. Photos are taken and she is given an identification number, then rewrapped, refastened into the sling under the helicopter and flown back to where she was captured then released. The whole process from capture to release takes approximately 60 minutes.

Aerial capturing and collaring bighorn sheep requires lots of time, money and effort. The answer to why we do it is best summed up by Randy Botta, Senior Wildlife Biologist, CDFW, who says "This effort allows us to gain the most accurate look at animals over a wide geographic area.” The Jacumba Mountains Wilderness, managed by the BLM, covers approximately 31,358 acres. Now imagine this landscape as steep, rocky and dry, and you have a good picture of Peninsular bighorn sheep habitat. The ruggedness of the environment and size of the habitat area, plus restrictions on vehicular use in the Jacumba Mountains Wilderness, make capturing sheep on foot impossible, even for the most intrepid of biologists. Using helicopters to capture large animals in difficult terrain is a proven method widely used by wildlife biologists throughout the western U.S.

Peninsular bighorn sheep were listed under the Endangered Species Act in 1998 based on significant a significant population decline from more than 1100 sheep in the 1970s down to about 335 in the late 1990s. Among the causes of the decline were: habitat loss and fragmentation, disease and predation.

The CDFW, as part of their regional monitoring program, is using fixed wing aircraft, ground based portable GPS receiver stations and biologists equipped with portable computers to help monitor bighorn sheep after collaring. The GPS data gathered provides location data that allows wildlife biologists to identify movements and habitat use areas within the Jacumba Mountains Wilderness and across the border into Mexico, relative to sensitive times of the year such as the rutting and lambing seasons. With this information we will be able to implement effective management of those areas in order to reduce or eliminate stressors such as habitat degradation and human/bighorn sheep interactions. In addition, the data may help us determine if, or how much, roads and interstate highways may be acting as barriers to movement. This type of information can help identify locations where future road crossings could be constructed to reduce or eliminate those barrier effects.

This is one of several actions being undertaken to recover this species. Currently, there are about 955 sheep in the Peninsular Ranges population of desert bighorn sheep.

The aerial capture and collaring of the Peninsular bighorn sheep is a cooperative effort between the Service's Carlsbad Fish and Wildlife Office, CDFW, BLM, and Customs and Border Protection. This effort will continue through fall 2014.

To learn more cool facts about bighorn sheep, its current status, and work being done to monitor the species, check out these websites -

The Service completed a status review of the species in 2011 - http://ecos.fws.gov/docs/five_year_review/doc3637.pdf

CDFW - http://www.dfg.ca.gov/wildlife/Bighorn/Desert/Peninsular/

 Patrick Gower is a wildlife biologist at the Carlsbad Fish and Wildlife Office in Carlsbad, California.


Contact Info: jane hendron, , jane_hendron@fws.gov



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