CORTEZ, Colo. (AP) - Mule deer numbers are declining in Southwest Colorado, with populations near Groundhog Reservoir and Mesa Verde National Park suffering the largest declines.
Trends for the past 15 years show a consistent drop in estimated populations in the region. Fly-over surveys, fawn-to-doe ratios, hunting data and on-the-ground observations are used to track population trends.
In 2011, Colorado Parks and Wildlife biologists estimated 22,700 mule deer regionally. For 2012, population estimates dropped to 21,100.
Mule deer numbers near Groundhog Reservoir and Mesa Verde National Park have been especially hard-hit.
Brad Weinmeister, a biologist in CPW’s Durango office, said the downward trend is likely attributable to the extended drought, less nutritious range and increasing development and populations.
“Since 2000, the forage has taken a huge hit, so that is a big portion of what is going on,” he said. “It’s a concern, and quite a bit of money has been spent trying to figure it out, but we have not pinpointed the problem.”
Hunters are reporting fewer mule deer in the field, and the dropping population numbers have led to fewer hunting permits for the animal.
“It has been harder to get mule deer permits,” said Michael Hall, owner of Westfork Outfitters. “We’re seeing less in some areas, but there has been an increase of mature animals.”
One bright spot is that fawn-doe rations for mule deer populations in the Groundhog area seem to be recovering somewhat. In 2012, data showed a ratio of 30 fawns to 100 does, while 2013 is showing 50 fawns per 100 does.
Deer suffer more during winter. Unlike elk, which are generalists, deer are more finicky and rely more on shrubs such as sage, mountain mahogany and serviceberry. In winter, they don’t digest grasses as well, Weinmeister said.
Officials say the recent expansion in housing developments, gas-and-oil production, recreation trails and roads are threats to mule deer.
“We’re all guilty of it. The last 10 to 20 years there has been a lot of growth in homes in the country with the new roads, driveways, dogs, horse pastures and traffic. It takes away habitat, and puts stress on the animal,” Weinmeister said.
Winter range for deer and elk is sometimes closed to vehicles, such as in the House Creek area, or to hikers and bikers, such as in the Animas Mountain and Horse Gulch areas in Durango, but the recent dry weather has led to violations of closed winter ranges by hikers and bikers, said Shannon Borders, a Bureau of Land Management spokeswoman.
In the Pagosa Springs area, recent studies have been done on mule deer migration patterns using radio collars.
Aran Johnson, a biologist with the Southern Ute Wildlife Department, conducted a 10-year survey where 89 deer were fitted with GPS collars in the Piedra River area and monitored to determine seasonal ranges and migration patterns.