Oregon's Failing Mule Deer Population


It should come as no surprise to anyone who has recently held an Oregon mule deer, that the population is in a bad place. A large part of Oregon has fallen below 50% of the recommended population objectives set forth by Fish and Wildlife. Additionally, some of what was Oregon's best mule deer units are now in the realm of 25% of herd objectives. Meanwhile, tag quotas haven't changed much for archery or rifle hunters in recent years.

Some areas have become bad enough, that it feels like hunting for them is approaching the point of unethical for myself as a hunter. This winter I have spent some time exploring the herd estimates, and historical data of Oregon's mule deer populations, and this is a summary of what I have found so far.

Mule Deer Buck
Mule Deer Buck

Background Info

Geography

To provide some important ground work for those less familiar with the stat of Oregon, I think it is important to touch on the geographical distribution of mule deer first. Oregon is divided significantly by the Cascade mountain range, which consists of almost entirely volcanic formations. The mountain range runs 260 miles North to South through the state, and includes Oregon's highest peaks. From the crest of the range eastward is the official line for mule deer in Oregon. To the west blacktail deer are the main species, but there is certainly some interbreeding among the two species within the cascades.

Mountainous Mule Deer Habitat in Eastern Oregon
Mule Deer Habitat in Eastern Oregon

The mule deer habitat of Oregon in terms of broad range, makes up about 2/3 of the state in total. The topography is vast and contains everything from high desert, to alpine high country, to dense coniferous forests. Until more recently, white-tailed deer weren't found in much abundance on the eastern side of Oregon. That is changing however, as whitetail deer seem to be thriving in areas of Northeastern Oregon, especially at lower elevations.

Predator Management

Also not to the surprise of those familiar with Oregon, is the lack of predator control. This comes mostly by the way of big game predation, although coyotes certainly do have some impact as well. In 1995, Oregon voters passed Measure 18 in November of 1994. Measure 18 banned the use of bait and hounds for hunting both black bears and mountain lions. Without question, this bill has had a significant impact on ungulate populations throughout both the eastern and western sides of the state alike.

Before measure 18, Oregon's mule deer population was estimated at around 250,000 according to the best historical data I can find from ODFW. In the years just prior though, the population had spike a few times to around or over the 300k mark for mule deer, which was approaching 100% of the management objective set by ODFW of 337,000.

The predator issue to me, is very hard to put on the management of ODFW, as their hands have been legally tied by the Oregon political system and its voters. A poor turnout by hunters and those in favor of hunting in1994 however, is largely to blame. Both black bears and mountain lions are having a large predatory effect on Oregon's mule deer currently. However, for a few reasons, I think mountain lions are the more to blame than possibly anything else for many reasons I will discuss later on.

Management Objectives

I specifically have avoided research into the population levels of the 1960s and 1970s because I doubt the ability to recover herds to those numbers exists. The 1960s may have been the perfect storm for mule deer as seen across the western United States, and the habitat and cultural acceptance of today will likely not align to support management numbers of 500,000 or higher in Oregon.

Currently, according to the latest info provided by ODFW, management objectives for Oregon's entire mule deer population sit at 337,000. The last provided population estimate for all combined game units with mule deer, recorded in 2018 190,325. This puts the state as a whole at 56.4% of management objective for mule deer. Last time I checked 56% doesn't exactly qualify as passing in any other sort of measurable metric. This number is down significantly from just four years earlier, where the population estimate was 231,241 (69%). In those 4 years populations are estimated to have decreased by about 18% statewide.

Glaring Issues

Predation

I feel like I am preparing to beat a dead horse with the predation problem, but it has its merit. One point in the data that really sticks out to me in regard to this is the fawn per 100 does. ODFW's mule deer plan suggests a minimum of about 35-40 fawns per 100 does for management objective, depending on the unit. With almost no exception, the data estimates that the mule deer in Oregon routinely provide fawn to doe ratios well in excess of that, often over 50 per 100.

Those deer are going somewhere, and I can't put that much blame on hunting in general, because very few antlerless tags, especially for mule deer, are given in Oregon annually. This suggests the mortality and decline is coming from somewhere else when it regards mule deer, rather than lack of reproduction.

Mountain Lions

I mentioned above the predator management limitations in Oregon. Mountain lion populations are often the first to get the finger pointed at them, and for good reason. Cougar populations have gone from an estimated total of around 3,000 in 1994, to a conservative estimate of 6,400 currently. That 113% increase statewide has occurred after years of a very stable population in the 2,000-3,000 total 1994 and prior.

Mountain lions are incredible animals, and in no way do I want to see them go away. However, some simple math with a conservative estimate of 3 kills per month, would put the mountain lion population at 230,000 ungulate kills per year. Plenty of research shows that mountain lions predate heavily on not just deer, but elk and bighorn sheep as well. Either way I think it is generally safe to assume that 50% or more of that total comes from deer. In terms of mule deer alone, this could easily be 80,000+ annually, which is nearing 50% of the total population.

Mountain lion populations are very heavy especially in parts of Northeastern Oregon, where deer population are suffering as much as anywhere. The greatest problem with the mountain lion population is the difficulty to hunt them currently. ODFW has done about all they can by opening the season for 365 days a year, and providing extremely cheap tag prices for both residents and non-residents alike.

Spring Bear Paw Shown after a successful hunt.
Spring Bear Hunting Can be Very Effective in Reducing Ungulate Predation

Black Bears

Bears alternatively, have a much shorter window of predation, and it mostly involves fawns in the spring. Bears are also much easier to hunt, and with some work can be taken relatively routinely by proficient hunters. There is no doubt that they have an impact, but my issue with them lies more with ODFW management.

Bear populations in Oregon are incredibly robust, and they are more easily managed inside the current legal methods of the state. What I can not understand, is why spring bear tags are so limited in much of the state, rather than placed on a quota system. A quota would get your most successful and knowledgeable hunters in the field every year to help manage the population. Spring bear hunting also provides the ability to target bears that specifically prey on fawns and calves repeatedly. This makes it very effective in helping ungulate populations avoid some additional predation.

Aggressive boars have been documented to kill well in excess of 30 fawns or calves each during the spring. One targeted spring bear hunter can make a lot of difference in this manner, without a negative effect on the bear population.

Wolves

There's not much I can say here, other than that they have an impact. Exactly how much on deer I don't know, but I do know I find wolf killed deer in Oregon. Currently they're illegal to hunt, and too much red tape is in place for ODFW to make a drastic impact on them currently. Simply put, they're here, and they aren't helping out the deer any.

Tag Allocations

I assume we all like to hunt deer if this topic concerns you, but at some point I feel like something needs to be done to limit hunters when the situation calls for it. This is the primary job of ODFW, and it some units its baffling to me why tags have not been reduced. Let's look at an example.

Pine Creek- Unit 62

Pine creek had an estimated population of 2,427 mule deer in 2014. This was 66% of its management objective of 3700. The last estimated population for pine creek was a shocking 890 deer. There is 193 more rifle tags available for pine creek this year, with unlimited over the counter archery hunting as well. With an estimate of 8 bucks per 100 does, that means ODFW estimates that there is about 71 bucks in the entire unit that a combined 500+ archery and rifle hunters will be chasing around. This unit is also nowhere near small in size, and encompasses some phenomenal deer habitat in the southern end of hells canyon. It also holds copious amounts of bears, wolves, and mountain lions. Its neighboring unit, Keating, isn't much different.

Mule Deer Doe
Mule Deer Doe from NE Oregon

Concluding Thoughts

I don't have the answers to fix this problem per say, and if it were that easy someone would have already done it. However, I'm far from optimistic about deer hunting in Oregon this upcoming year. It really is incredible to go to somewhere like Idaho, in areas where the deer have said to be decimated, and realize I'm seeing 3-5 times the amount of deer that I typically see in Oregon.

It's also disappointing to see areas, like the Minam unit, which was once one of Oregon's top trophy mule deer producers. The unit can now be drawn with no points for a rifle hunt, and turning up a single 1.5 year old buck can take half a week in a lot of the unit. There are still some desert and pine forest units that have fairly healthy deer populations, but for the most part the eastern side of state has become fairly bleak in respect to mule deer.

With the exception of some noise being made by hunters, the mule deer seem to silently be fading away in much of the state while everyone stares at the Salmon that are disappearing from the rivers in a similar fashion.

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