Vaughan uses a land-based population research technique to look at the age and sex distribution of the Grand Canyon's bighorn sheep. This lamb-to-ewe ratio gives Vaughan an idea of how well reproduction is going for a given year. "Basically, I count and estimate the lamb-to-ewe ratio in April right after they are born," explains Vaughan. "Then, I come back three-to-six months later and do a recount of the area." This data provides Vaughan with an analysis of the animals' survival rates, which is critical information for wildlife managers.
The research requires a two-week long rafting trip twice a year down the Colorado River. He, along with participating Virginia Tech graduate students, survey the 200-mile stretch by land, followed by a helicopter count. This method helps Vaughan figure in any miscalculations or errors in his estimates.
"Prior to our research, there had always been strict helicopter restrictions in the Grand Canyon," explains Vaughan. "As a result, the National Park Service had no information on the Grand Canyon's sheep population." While the restrictions are still in place, the Park Service allowed Vaughan's research team to fly low enough in the Canyon to count sheep.
It was not very difficult to find graduate students willing to participate in this research project. "We spent the days hiking up the surrounding canyons in search of hidden sheep," adds Virginia Tech fisheries and wildlife sciences graduate student, Daniel Lee. "The nights were spent camping under the stars."
A group of 18-20 other scientists joined Vaughan on the rafting trip. Those researchers were doing a Mexican Spotted Owl search, mule/deer pellet surveys, and frog and lizard surveys.
Vaughan received funding from the National Park Service and the United States Geological Survey. The USGS serves the nation by providing reliable scientific information to describe and understand the earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect the quality of life.
Written by Sarah Kayser, Intern in the Office of University Relations
PR CONTACT: Lynn Davis, 540-231-6157, davisl@vt.edu