Nebraskaland

72 NEBRASKAland • APRIL 2017 T he Nebraska Game and Parks Commission got up-close and personal with 20 bighorn sheep ewes this winter in an effort to track their future offspring. The goal is to get a handle on the species' population struggles in the Pine Ridge area of northwestern Nebraska. With the help of a helicopter wildlife capturing crew and others, Commission staff on Feb. 14-16 equipped 20 pregnant female sheep with a device to help immediately detect when lambs are born. The Commission has staged numerous bighorn sheep captures in past years involving the installation of telemetry collars, but this is its first bighorn- monitoring project using this type of transmitter. The vaginal implant transmitter, often referred to by its acronym VIT, is a three-inch long tube designed to be inserted behind the fetus in the birthing canal. About the same diameter as a roll of dimes, it has an antenna and features two plastic wings to help it stay in place until a lamb is born. Upon birth, a change in the transmitter's temperature will trigger a frequency that indicates a lamb was born. Shortly after, Commission staff will race to the lamb in an attempt to equip it with a temporary tracking collar. By tracking the lambs, biologists hope to get a better idea of what is causing so many of them to die in the Pine Ridge area of Dawes and Sioux counties. Populations have struggled in that region in recent years and biologists believe no lambs survived the 2016 birthing season. Most have died within a couple of months of being born. Veterinarians from the Alliance Animal Clinic and Crawford Companion Animal Clinic, staff members of the Henry Doorly Zoo and the U.S. Department of Agriculture Animal and Plant Health Inspection Service, along with students from the Chadron State College's wildlife management program and other volunteers, joined Commission employees during the processing. The team, consisting of as many as 50 people at times, worked Ponderosa Wildlife Management Area and Fort Robinson State Park near Crawford on the first day, private property south of Whitney on the second, and U.S. Forest Service property near Chadron State Park on the third and final day. The group had intended to finish the project Wednesday, but were sidelined most of that day by helicopter mechanical problems. In addition to the 20 bighorns that were fitted with VITs, the effort netted another six ewes and five rams. The sheep were captured using a net fired from a gun, then hobbled and carried to the processing station hanging on a tether below the helicopter. Sedatives eased stress and intravenous fluids and ice lowered their high body temperatures. A mobile ultrasound machine helped determine if the ewes were pregnant. Each sheep's nose and throat were swabbed for bacteria testing, and blood samples were taken to determine DNA. The crew also administered antibiotics to combat any illnesses they might have. And, each sheep was equipped with telemetry collars and ear tags. The collars aid Commission wildlife technicians in their goal of locating each collared sheep at least once a week and the ear tags help with identification. Not only do biologists look forward to learning more from tracking the lambs, they hope to gain insights from test results from this week's captures, said Todd Nordeen, Commission big game research and disease program manager. The Pine Ridge herds have disease issues, and biologists hope to determine the exact pathogens to blame. Pasteurella pneumonia has been linked to bighorn sheep deaths throughout their ranges in North America, but other bacteria also cause problems. "We'll see when we get the test results back how many test positive for mycoplasma ovipneumoniae, in particular," Nordeen said. "Th at's another bacteria that sheep have been dealing with throughout the West and research is increasingly showing that it's one of the primary bacterium leading to die-offs and mortalities." Soon, bighorn sheep monitoring efforts will ramp up considerably in the Pine Ridge. "When spring comes, we're going to be out there every day tracking these collared ewes, especially when they isolate themselves and look like they're going to give birth," he said. "Then we'll be listening for the frequency of the Bighorn Sheep Get Implant Transmitters Biologists are able to tell when lambs are born due to new technology. Story and photos by Justin Haag The vaginal implant transmitter is designed to be ejected from a ewe upon the birth of a lamb. A change in its temperature triggers a signal to researchers using telemetry equipment.

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