Ungulate roundup

 

As 2012 begins, the various native ungulate species of the West are getting transplanted to new turf – and thinned out by diseases on their home ranges.  Here's a roundup of recent news about bighorns, pronghorns, deer, elk and bison.

In southern Colorado, recently-transplanted desert bighorn have joined forces with an existing bighorn band. In the rugged canyon of the Dolores River, biologists say there are now about 60 of the rare sheep, which are smaller than high-country bighorns and better adapted to dry conditions.

The state's Division of Parks and Wildlife transplanted 15 desert bighorns into the area in 2010 and another 15 in 2011 to increase overall genetic diversity. The fact that the newcomers joined up with an established herd bodes well for their survival – instead of having to figure out the location of water, food, and escape routes in an unfamiliar habitat, they can learn from the resident sheep.

In December, 42 bighorn sheep were captured on the Navajo Reservation in Utah. Twenty were tagged and released in Peeples Canyon in Arizona. Three went to the tribe's zoo, and 19 were released near the Upper San Juan River in southeast Utah. The Peeples Canyon area also has a "robust" population of mountain lions, which find bighorns tasty.  The state's Game and Fish Commission is now trying to reduce cougar numbers in that area and other important bighorn habitat by letting hunters use artificial lights at night and bag more than one cougar per year.

Ewe-hauling is also happening in Texas, where 95 desert bighorn were rounded up recently in the Beach Mountains. They were released in Big Bend Ranch State Park; the state's goal is to double the number of bighorn in West Texas mountain ranges, to 3,000. Eight of the sheep have tracking collars:

"Having the basic information is important, but we will also be able to use the data for future location efforts," (researcher Thomas) Janke said. "By determining the range, the elevation and the steepness of slope, we will be able learn what mountain ranges are most suitable for locating more sheep."

Meanwhile, in Montana, Gov. Brian Schweitzer wants to do some buffalo-shuffling, but only within his state's borders. There are about 3,700 bison in Yellowstone National Park, and when they leave the park in search of winter forage, they often end up hazed and even slaughtered, in the name of protecting the livestock industry from brucellosis. Schweitzer would like to see the genetically-pure Yellowstone bison quarantined and tested after the bison hunt has ended, with the diseased animals slaughtered and some of the healthy ones relocated. But the Department of Interior has other plans for Yellowstone bison – the Wind River reservation in Wyoming, and the South Unit of Badlands National Park in South Dakota. Some could even end up in Great Sand Dunes National Park in Colorado. Schweitzer doesn't like the idea; he's said that Montana's bison don't belong to the feds and should stay in his state.

While buffalo may get to roam more widely in Montana, Arizona's working on expanding the range where antelope play. For the first time in a century, the King Valley in the Kofa National Wildlife Refuge holds Sonoran pronghorn. The desert animals nearly became extinct in 2002. Now, a dozen pronghorn have been moved from the Cabeza Prieta National Wildlife Refuge to a captive breeding facility in King Valley. Next year their offspring will be released.

Speedgoats are making headway in Washington state too. Safari Club International and the Yakama Nation released 99 pronghorn on the Yakama reservation last January, after moving them 700 miles from a capture site in Nevada. A year later, they seem to be doing well and reportedly produced a good crop of fawns this summer. Next month, the tribe and SCI are going back to Nevada to get another 150 pronghorn to augment the herd.

Unfortunately, ungulate populations are shrinking in some areas due to the spread of disease. In eastern Montana and the Northern Plains, an outbreak of epizootic hemorrhagic disease has killed thousands of whitetail deer. Abnormally warm, wet weather has encouraged the proliferation of the biting midges that carry the disease, which doesn't harm humans or livestock. Although it's most damaging to whitetails, it also infects mule deer, bighorns, elk and pronghorn; it kills most infected animals within a few days by causing severe internal bleeding.

And that notorious slaughterer of bighorn sheep, pneumonia, appears to have spread into Yellowstone National Park. The Montana Division of Fish, Wildlife and Parks suspects that domestic sheep may have given the disease to their wild cousins. State biologists have been tracking sheep in the Gardiner area since early December, when observers reported coughing bighorn. They killed five sick sheep to keep them from passing it along to healthy flock members, but now it looks like the mostly-fatal illness is spreading into the park. The Associated Press reports that a bighorn lamb in the park has pneumonia -- researchers fear the sickness could spread rapidly.

Another scourge that kills Western deer, elk, and moose, chronic wasting disease, continues its steady march across the U.S..  It was first identified in the late 1960s in captive mule deer in Fort Collins, Colo., and by 1997 was found in Colorado, Wyoming and South Dakota. The fatal illness moved south into New Mexico in 2002 and has been spreading relentlessly ever since. Now, the disease has shown up in three more counties in central Nebraska, which is the leading edge of the eastward expansion.

You might wonder whether all this transplanting of ungulates has anything to do with the spreading of ungulate diseases. As the expansion of chronic wasting disease among deer populations shows, wildlife diseases manage to spread even when humans are not shuffling animals from one place to another (generally no one transplants deer since they're so common -- Texas poachers excepted). But the recent movie Contagion underlines the point that the movement of even one sick person (or bird, or mammal) into another, uninfected population can help those diseases expand much more rapidly. It may not always be practical to quarantine transplanted wild ungulates before releasing them -- but it may be worthwhile in a world in which we transport animals on journeys they'd never make on their own ...

Jodi Peterson is HCN's managing editor.

Image of Utah bighorn sheep courtesy Flickr user Aditi-the-Stargazer

Image of Sonoran pronghorn courtesy Flickr user Florin Chelaru