Mule deer remain a common sight in Bend, but statistics show that their numbers are down dramatically in Central Oregon over the past five years.

The number of mule deer in four defined areas of Central Oregon managed by the Oregon Department of Fish and Wildlife declined 33% since 2017. They currently number 10,986 in the latest estimates, compared to 16,521 five years ago, according to data from ODFW biologist Andrew Walch. The mule deer population has fallen by 51% compared to 2002 population estimates.

The numbers were tabulated with helicopter surveys and are based on deer range winter habitat. So-called “town deer,” those that make their home in Bend or other urban communities, are not included in the estimates.

The mule deer counts are conducted on a rotating basis annually so a new population estimate becomes available every three years.

The Oregon Department of Fish and Wildlife would like to see 27,000 mule deer for the four wildlife management units, which include the Metolius, Upper Deschutes, Paulina, and North Wagontire Units.

The target number, also called a population management objective, is a compromise that tries to maintain deer and elk numbers at levels compatible with primary uses of the land. It is not the maximum number of animals a unit can support.

The management objective also factors in habitat availability, carrying capacity, and the amount of damage the animals cause to private property, while also trying to maximize recreational benefits such as hunting and wildlife viewing.

Preventing the serious depletion of wildlife is another factor that plays into the target number.

But with only around 11,000 mule deer in the four units, the population is well below objectives.

“This number is the product of a public process that included hunters, landowners and other stakeholders,” said Walch.

“As you can see, we are currently at about 40% of management objective overall here in the Bend District.”

Elk populations in the Central Oregon Cascades, by comparison, are steady to slightly increasing in recent years, ODFW reports.

A wildlife inventory, now scheduled to be conducted next year, could help Deschutes County determine protections needed for mule deer. The inventories often form the basis for developmental codes and include not only numbers of animals but also migration patterns.

The mule deer decline comes as Central Oregon experiences an unprecedented expansion of housing developments, new roads, and other urban infrastructure built in an effort to keep pace with an insatiable demand for homes in the area. A rise in remote work has untethered thousands of people from their jobs in larger cities, and Bend has become a popular place to relocate.

Homes, fencing, and other development can cut off mule deer migration patterns, causing stress on the animals, and making them more susceptible to predation and disease, according to the Oregon Department of Fish and Wildlife.

Adenovirus Hemorrhagic Disease is cited as one of the more significant problems for mule deer.

“We see cases of AHD every year throughout the area, especially in places where people are feeding deer, causing them to congregate,” said Walch.

“We only hear about the sick or dead deer in peoples’ yards, so it’s hard to say how much an impact it has on deer populations out of town in the forest,” he adds.

Other factors impacting the numbers include increased year-round disturbance, drought, roadkill and changes in public and private land management.

ODFW says hunting has not had a significant impact on mule deer declines. The state agency said it has “drastically” reduced hunting tags on mule deer over the past couple of decades.

“We only hunt bucks, and we monitor the buck to doe ratio every fall to ensure that there are enough bucks present to breed the does,” said Walch. “Low adult doe and fawn survival are what is driving the population decrease. The limited hunting is not a primary cause of the population decline.”

More significant, said Walch, are deer strikes by vehicles. He cites a deer study that ran from 2005 to 2013 in south-central Oregon that showed 18% of collared mule deer died as a result of roadkill.

“Traffic volume on highways and backroads has certainly increased in the 10 years since that study,” he said.

Central Oregon made some strides in reconnecting migration patterns by building wildlife crossings under U.S. Highway 97. Crossings are located near Lava Butte, Sunriver, and Gilchrist. The crossings have helped cut animal strikes by 85% in those areas of highway, according to Oregon Department of Transportation data.

Caitlyn Burford, a spokesperson for Central Oregon LandWatch, said a major concern for her nonprofit is that proposed logging and national forest management policies in Central Oregon could accelerate a decline in mule deer numbers.

A certain amount of tree cover is needed to provide security and hiding cover, thermal cover and foraging potential to sustain the herd’s lifecycle, said Burford. These are under threat by national forest management policy.

“As such, we continually monitor proposed logging and management projects in the Deschutes and Ochoco national forests and ensure they align with forest plans,” said Burford. “The plans are designed to consider wildlife when conducting projects on public forest land.”