Researchers capture more deer for CWD study

By Stephen Clearheart Johnson
North Forty News

On a crisp clear February morning near the headwaters of Boxelder Creek, a unique work team gathered to capture a second group of mule deer for Colorado State University's new study of chronic wasting disease.

They hadn't expected to return to the field so soon after the first sample taken in the fall of 2009, but the results were so promising they moved quickly to add a second sample.

Dr. Thomas Hobbs of CSU's Natural Resource Ecology Laboratory explained that results from both the first samples and from the radio-collar monitors were much better than expected.

The team Hobbs gathered consisted of research assistants and graduate students, a veterinary team from the Division of Wildlife and a helicopter netgunning crew. His goal was to add a second sample of 40 or more deer to the 100 from the first capture.

To capture deer, researchers first drop a net from a hovering helicopter. A wrangler quickly hobbles and blindfolds the animal and gives it a light sedative to calm it until it can be transferred to a sling and ferried to the medical testing site.

At the site, the team takes blood and tissue samples, checks vital signs, and attaches a radio collar weighing less than a pound. Working quickly, they release the animal into the wild, usually within 20 minutes.

The team is particularly careful in monitoring the health and condition of the captured deer. "We like to capture in cold weather to avoid heat stressing the animals," said research assistant Jill Lackett.

Researchers monitor the signals up to three times per week, taking hand-held receivers into the field. "Within three days of the first capture," Hobbs said, "we received 'I am alive' signals from 98 of the 100 animals." If the animal dies, a motion sensor in the collar changes the signal. Researchers will locate the animal on the ground, take additional samples and determine the cause of death.

Hobbs has nothing but praise for the helicopter crew, Alaska-based Quicksilver Air. He noted, "No animals were injured in the first capture," even though losses normally run 1 to 3 percent.

The team will recapture collared deer after a year by following the radio signals. Further blood and tissue samples will be taken. Hunters are advised that if they bag such an animal, they should report it immediately for inclusion in the study.

The study seeks to gather information on how the disease is transmitted, what role genetics may play and whether CWD causes long-term declines in the population of mule deer.