The mule deer population in Deschutes County is about half of what it was 20 years ago, according to the Oregon Department of Fish and Wildlife. There were about 11,000 mule deer in the county in August 2022, excluding "town deer" that have acclimated to human environments. In 2020 Deschutes County planned to update its data for the winter range of mule deer to better understand current habitat and migration patterns.
An Interagency Working Group of biologists and state agencies released the new inventory of mule deer habitat in the summer of 2021. Next, the county planned to put that data into action but delayed the process to focus on other time-sensitive projects. On May 11, the Deschutes County Planning Commission recommended new zoning regulations to protect mule deer habitat. But, the Deschutes County Board of Commissioners voted 2-1 to abandon the project entirely at a June 26 meeting.
"I've come to the conclusion that I'd maybe like to abandon it. It is a very engaging topic, but the problem that I come to is that we have a new combining zone and no matter what we negotiate, however it gets put on paper, it can be used in the future to [say], 'you can't do that, you're in the mule deer combining zone,'" Deschutes County Commissioner Tony DeBone said at the meeting.
The proposed inventory included 188,132 acres, about 43% of which was on private land. The regulations are minimal for properties that are less than 20 acres in residential zones, but they do limit some commercial activities, create different standards for divisions of larger lots and create fencing standards for new buildings. Deschutes County Commissioner Phil Chang, the lone vote against abandoning the program, argued that the restrictions aren't particularly restrictive and that the commission is responsible for safeguarding the county's natural heritage.
"If you have rights to develop a certain number of dwellings you will still have those rights after this process is completed. The configuration might be a little different, there might be a requirement if you own hundreds of acres of [rural residential 10-acre minimum] zoned lands, instead of putting one house per 10 acres you might have to cluster," Chang said.
Central Oregon LandWatch, a nonprofit that advocates for conservation and through Oregon's land use system, advocated for an update to the wildlife inventory before it went to the planning commission. On a webpage dedicated to the issue, LandWatch said it's generally supportive of the mule deer inventory update, but also said there are areas it could be improved. Rory Isbell, a staff attorney at LandWatch, said the protections aren't as strong as currently existing wildlife overlay zones, which are scattered across the county to conserve the habitat of specific species. It's been more than 30 years since the county updated its wildlife inventories.
"The proposed overlay zone that county staff presented to the planning commission would have had very modest impacts to property rights and development rights," said Isbell. "It actually proposed weaker standards. So it allowed for more development than the existing wildlife overlay zone does."
Commissioners DeBone and Patti Adair raised concerns about the causes of declining mule deer populations, and voiced support for a citizen work group at that meeting and again at a July 5 meeting. An ODFW study estimated mule deer fatalities between 2005 and 2013 were caused by natural predation (32%), poaching (22%), hunting (20%), vehicle strikes (18%) and other (8%). The causes of death, however, can be symptoms of the habitat a deer exists in.
"Habitat is kind of the underlying foundation of all wildlife biology," said Andrew Walch, a wildlife biologist at the ODFW.
Walch said mule deer are consistent in their migratory range, unlike their more adaptable cousins, the White-tailed deer. Mule deer generally stay up in the mountains during the summer and move to lower elevations in the winter to avoid the snowpack. Winters, even in good years, are tough times for mule deer and they're likely to have decreased fitness throughout the season, which is even more impactful with insufficient areas to eat and rest.
There are other factors at play, though. More cougars are living in Central Oregon after hunting them was criminalized in 1994, leading to more predation. Central Oregon rapidly developed, increasing traffic that could increase collisions with deer. Still, Walch said habitat preservation is the top concern.
"It's death by 1,000 cuts," Walch said. "All these different things are part of the equation but habitat and the fitness of those deer, overall, is kind of a driver of a lot of those things. If a deer has good habitat and migration routes and is in good shape, it's less likely to succumb to disease or predation and those sorts of things."