Mule Deer Survival Study

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The Colorado Division of Wildlife (DOW) will use a helicopter next week to capture mule deer in Fremont, Chafee and Teller counties.

Biologists are putting radio collars on deer in the Upper Arkansas River Basin as part of a study to determine why Colorado’s mule deer population declined during the 1990s.

“In light of the heightened concern about low-flying aircraft, we want to alert the public that we will be using a white helicopter with a blue belly,” said DOW biologist Jack Vayhinger. “In the past, citizens have called the police with concerns about the aircraft harassing wildlife. We just want to let the public know this operation is part of a long-term scientific study.”

The helicopter will be operating in the Cañon City area beginning Monday, Jan. 10. Flights will continue up river into the Texas Creek, Buena Vista, Salida and Leadville areas as the week progresses.

Wildlife biologists use the helicopters to locate deer before dropping a net over them. Once a deer is in the net, the helicopter lands and biologists begin fitting the animal with a collar.

“Captured deer are freed within a matter of minutes,” said Vayhinger.

Approximately 13 adult females and 60 fawns will be radio-collared in an area roughly bordered by Leadville, Fairplay, Salida and Cañon City.

This year, DOW biologists will also capture 20 elk in the Trout Creek Pass area to study movement patterns and response to habitat improvement projects.

“This year marks the sixth consecutive year of an on-going effort to provide survival data as part of our annual mule deer inventory effort,” Vayhinger added.

Other areas of the state that are part of the study include Middle Park, the Poudre River and the Uncompahgre Plateau. Most of the animals in the study are females and fawns, although the Uncompahgre Plateau study also includes yearling bucks.

The radio-collar transmitters enable biologists to check on deer from an airplane once a week. If a deer dies the signal changes, which makes it possible for a ground crew to locate the carcass, retrieve the collar and try to determine the cause of death.

Biologists hope to gain valuable, long-term information about the overall health of Colorado’s deer herds.

“We observed some interesting migration patterns during the first four years of the program, but our primary goal is to determine survival rates,” Vayhinger said. “Doe and fawn survival rates are critical factors in the computer models we use for managing deer herds.”

By monitoring deer survival rates from different areas of the state, DOW biologists have new insight into how survival rates differ according to habitat.