Deer Friendly - California Long-term Deer Population Trend

Long Term Trends in California's Deer Population

Recent Deer News and Population Estimates

The Long Decline The state's deer population has fallen from the peak of about 2 million around 1960 to around 475,000 (450,000 to 500,000) in 2023. The graph at right shows an historical population estimate for California deer. See page 167 for details. The estimate is part of an effort to build a statistical model to help understand the reasons for the decline of the California population. This article provides evidence that reduced timber harvests and forest management, along with skewed deer demographics in California have contributed to the long term decline of the deer population. Although neighboring states have experienced somewhat similar declines, data indicate that no state in the West or in the rest of the United States has seen their deer population fall as much as California in the modern era.

Deer hunting was suspended in 1917 to protect the population that had fallen to very low levels as a result of unregulated hunting. California has conducted a bucks only harvest in all but a few years since hunting was resumed in 1927. Although states often adjust the number of does taken in order to manage the population, no other state has pursued this policy for such a long time as California. As a variety of sources suggest, skewed age and sex demographics as for the California herd are considered to be problems by many deer managers. The state also applies a relatively high hunting pressure as measured by hunter success rate and compared to other states.

How Has Climate and Timber Production Related to the California Deer Population?

Habitat degradation due in part to forest management practices have long been associated with the decline of the deer population. A statistical correlation of the decline in timber removed from California lands accounts for 63 percent of the variation in the decline of the deer population, as measured by the annual buck harvest, from 1978 to 2016. Fire suppression and other forest management practices have reduced the amount of edge habitat that support deer and other species, significantly increasing forest density As illustrated by the graph below two factors, timber removed from California and drought, account for 75 percent of the variation in a two year moving average of the California buck harvest over 1978 to 2016.

Previous year timber removed (dotted line) declined in the early 1980s, followed by the buck harvest (solid line). Timber removed increased in the late 1980s, but a long drought reduced deer populations. The decline in timber removed around 2008 and subsequent increase starting around 2010 was associated with changing timber demand from the great recession and recovery. The buck harvest closely follows the pattern. Notably, the deer population increased in response to the increase in timber removed during the 2011 to 2016 even though there was a severe, long drought from December 27, 2011 to March 5th, 2019. It would be difficult to explain this population recovery without the timber data. Nevada estimated a population decline as a result of the drought in 2015.

The Problem of the Skewed Sex Ratio in California

One method used by deer managers to control deer populations is to change the ratio of buck to doe hunting licenses issued. Killing a large proportion of does will reduce fawn production in the following year, putting downward pressure on the population. Since one buck can impregnate many does, reducing the proportion of does killed and targeting bucks is typically used as a strategy to increase herd growth. Each buck can impregnate more than one doe. During the rebuilding of deer herds during the middle of the 1900’s, many states employed a bucks only harvest to enhance population growth. California is unique in that it is the only state that has pursued essentially a bucks only harvest for almost every year since 1927 when deer hunting was resumed after a 10 year hiatus designed to protect the herd from over hunting.

The national management trend is to balance herd demographics. Deer managers around the country often comment to the press about the dangers of persistent skewed demographics. A 2009 study of deer in Siskiyou county found only 3 percent bucks. Statistical evidence that the policy of long-term deer hunting targeting mostly bucks, as in California, has been a contributing factor to the decline of the deer population appears in this paper.

California has the most extreme policy of nearly bucks only hunting and the most dramatic long-term decline of its deer population compared to any other state. The paper also gives evidence that significantly higher relative hunting pressure, as measured by a hunter success rate that is often the lowest of all states, has contributed to the population decline. This 2019 study documents the low buck-to-doe ratio.

Hunting Pressure as a Factor in the Population Decline

In January, 2016, the state considered dropping the target number of deer tags for 2016 from 196,680 to 127,000. In 2014, the Game Commission authorized about twice as many buck tags as there are available bucks in the entire state. Given the history of a large number of tags issued, hunter success in California is often lower than in any other state. If California hunters had the national average hunting success rate, the wild herd would be wiped out. CDFW generates about $25 million in revenue annually from the sale of tags.

During the 1960's, when Idaho was selling too many tags to sustain the herd and overstating the population numbers. The people of the state pressured the agency, tag sales were reduced, the herd recovered. Same basic story in Colorado during the 1990's.

News and Studies Related to the Decline of

California's Deer Population

This population research on a private ranch in California illustrates the low buck-to-doe population ratio in the state:

Estimating Deer Populations Using Camera Traps and Natural Marks LT Macaulay, R Sollmann, RH Barrett - The Journal of Wildlife Management, 2019 California

... We estimated density at 7.7 deer/km2 in summer and 8.6 deer/km2 in fall. In the summer, home ranges were 2.3 km2 for females and fawns and 16.8 km2 for males. Home ranges constricted slightly in fall. We estimated a sex ratio of 12.5 males/100 females, and a ratio of 47.0 fawns/100 adult females. Bait increased baseline encounter rates (visits/week) by 3.7 times in summer and 4.95 times in fall. We found slightly higher densities of deer in our study area compared to other recent studies in more mountainous areas of California, and lower male:female sex ratios. This approach shows that commonly deployed camera traps can be used to quantify population characteristics, monitor populations, and inform harvest or habitat management decisions ...

A Native Community Preserves its Food Traditions November 21, 2017 California, Civil Eats

... Because the elk are currently under federal protection as a response to past over-hunting by white settlers, the Tolowa are denied the right to hunt ... “It is possible to sustainably harvest wild game with better management of the forest, prescribed burning, and responsible harvest,” says Guylish Bommelyn, a hunter and language teacher at the Tolowa Dee-ni’ Nation..,

Bambi vs. the mountain lion October 2, 2015 California, SFGate [reprint of an article from April, 1967]

... The State has an estimated one-and-a-half million deer. ... [note that the deer model estimated in the graph in the upper right put the 1967 deer population at around 1.5 million, the estimate above was presented before this information became available, providing an indicate of estimate reliability for our deer model] ...Under the bounty system, from 1907 until four years ago, California hunters collected from $20 to $60 each for slaying 12,461 mountain lions. (1963) ... Assembly Bill 940) ... would replace the four-year moratorium with permanent repeal...

Decline of California Deer, Big changes for Hunter Education in California May 2, 2015, Examiner

... Dave Casady a Dept. of Fish & Wildlife biologist made a presentation on a study he has been working on regarding the condition, and status of the blacktail deer in a 400 sq mile area of the Mendocino national Forest. This data will be covered in full in a later report, however, the main points coming out of the data was as many hunters have suspected the size of the California Blacktail herd is diminishing by about 10% each year, in this area...

Black-tailed deer population assessment in the Mendocino National Forest, California May, 2015 Wittmer ... ResearchGate

... Our results show that deer in the Mendocino National Forest are currently declining in abundance. We found evidence that the decline is caused by high mortalities due to predation in all age classes. We also found bottom-up effects contributing to the decline. Based on the past history of black-tailed deer in the area and their persistence over evolutionary time, we suggest that the current decline is part of longer-term fluctuations described by earlier researchers...

Deer populations continue decline November 3, 2014 California, Siskiyou Daily

... A dramatic decline in the Siskiyou County deer populations over two decades has triggered concern and a proposed management plan in an attempt to find conclusive evidence as to why the declining numbers continue to persist ... increasing trends in selenium deficiency and predator impacts are of interest ...

B-zone deer population holding steady September 17, 2014 California, Lake County Record Bee

... The hunter success rate in 2013 for the B zones was 23 percent. Greg Giusti of Kelseyville hunted during the bow season in the B zone at Klamath Mountains and his group counted a total of 557 deer, 24 being legal bucks forked horn or better, during a four-day period. They also counted 60 spike bucks. [About 15% bucks, 4% mature bucks, not a sustainable demographic] ...

CDFA Reports that the Population is Stable to Slightly Declining June, 2013

Although the CDFW's own data show about a 50 percent decline in the deer population from 1990 to 2012, CDFW reported to the Mule Deer Working Group that: "California’s deer population has been stable to slightly declining for at least the last 20 years. Most apparent is the reduction in migratory deer populations in the northern and eastern parts of the state." [see California Status Update]. The goal of the working group is to "to provide an update on the general range-wide status of mule and black-tailed deer." The California data misrepresents the state's deer status.

California Zone A deer season opens Saturday August 5, 2014 Lake County Record Bee

... The drought has had a major impact on the county's and state's deer population... Approximately 250 bucks were taken in the county in Zone A in 2013, a far cry from the 1950s when the county produced 1,500 bucks annually. Drought, loss of habitat, predators and the increasing human population all have taken their toll on the county's diminishing deer herd... the limit is two bucks forked horn or better...

Deer Diary, California Deer History June 18, 2014 California, Good Times

... the Huichol. Before the arrival of the Spanish in the 16th century, more than 10,000 people lived on California’s coast between Big Sur and San Francisco. Dating back some 15,000 years ... The deer is the most sacred of animals for the Huichols, the symbol for the heart, intuition, and higher self, says Secunda ...

Why no deer hunting during rut in California? January 14, 2014 Willows Journal

... According to Game Species Conservation Program Manager Craig Stowers, seasons are set with certain harvest objectives in mind. Later in the season as the animals go into the rut (breeding period) they become more bold in their attempts to find a mate, and are thus easier to hunt. If the season was held during the rut, the hunter harvest success rate would be higher, and fewer hunters would be able to hunt before the harvest objectives were reached....

Pumas can't order in, so they eat out May 11, 2014 California, San Francisco Gate

... California's deer population has declined from 2 million in the 1960s to 850,000 in the 1990s and an estimated 445,000 this past winter, according to DFW... The big question is for areas where there are hungry mountain lions, yet there aren't enough deer left to go around: What will the lions eat next? ...

Fish and Game Commission Adopts 2014 Big-Game Tag Quotas April 18, 2014 California, CDFW News

... The California Fish and Game Commission (FGC) finalized big-game tag quotas at their April 15 meeting in Ventura. A total of 204,337 deer [FGC has issued about twice as many tags to kill bucks as there are available bucks in the state. Hunter success in California is estimated at from 9 to 17 percent, the lowest success rate in the United States where average hunter success is about 55 percent. Other states adjust the number of tags issued in order to maintain deer populations. If California hunters have the average national success rate the wild herd will be wiped out.],

Reduction in the number of deer tags recommended April 9, 2014 California, The Trinity Journal

... Concerned that Trinity County deer herds appear to have experienced a drastic decline in numbers over the past 20 years, the Trinity County Fish & Game Advisory Commission has recommended to the California Fish & Game Commission a reduction in the number of deer hunt tags available here from two tags per person to one and a reduced season in the state regulations scheduled for update this year...

Studies planned to monitor Siskiyou deer herds April 4, 2014 California, Siskiyou Daily

... Siskiyou County’s deer herds have experienced declining population trends, and two large-scale studies are expected ... helicopter surveys in 2009 covering 308 miles found only 163 deer, with males constituting less than 3 percent of the count... there are also efforts underway at the state level to provide a state-wide deer strategy, but it has been stalled multiple times...

California Deer Winter, 2014, The Official Publication of the California Deer Association

... “Where are the deer?” There were no signs of predators … There has been no development … The feed was plentiful and in good condition. The only thing that was lacking was deer sign...

California Black-tailed Deer, where are they? September 15, 2012 Examiner.com, Jeffrey Banke

... As a photographer ... searching for black-tailed deer to photograph became more and more difficult to locate animals this year ... interviewing Sierra Pacific employees who are in the woods logging for months at a time who have seen very few deer confirm this observers own research. It would seem in conclusion, that if we do not have some radical changes in both the wildlife management approach by the DFG ... then we are on a continuing downward spiral... [Jeff Banke is a freelance photographer who has been teaching Hunter Education for the California Dept. of Fish & Game for 18 years, is one of only 7 Master Instructors in the State.]

Predators and Prey—A Case of Imbalance, Mountain Lions and the North Kings Deer Herd "Forest Research West", June 1989

In the study area on the west slope of the Sierra Nevada, apparently mountain lion numbers have increased while deer numbers declined to about one-eighth their peak numbers in the 1950s.. In the study area on the west slope of the Sierra Nevada, apparently mountain lion numbers have increased while deer numbers declined to about one-eighth their peak numbers in the 1950s. Neal, along with George Steger (also with PSW), studied the California mule deer in the Sierra Nevada from 1970 to 1985 as part of an interagency effort to reverse the decline. This effort showed that the decline was primarily due to loss of fawns during the first 6-8 months of life.

A paper describing how changing forest management practices have reduced deer habitat in California, CDFG, Habitat Guidelines for Mule Deer, 2007

Drought May Account for Uptick in Deer Harvest

The reported deer harvest has risen from the record low of 10,892 in 2010, but the increase corresponds the the persistent drought in California that has worsened significantly into 2014. Deer searching for food and water are more active and so are more likely to by killed during the hunt. Deer collisions reported to the California Roadkill Observation System in 2014 have risen dramatcially over previous years, indicating the deer are moving around in search of food and water.

California Drought Greatly Affecting Wildlife May 15, 2014 Guardian Liberty Voice

... inland California’s already declining population of deer is having a very difficult time with a loss of vegetation and sufficient water supplies. Deer will be forced to migrate to new land in search of adequate food and water ...

The West Coast and California in the 1700s October 28, 2018 San Mateo Daily Journal

... mid-1700s ... San Francisco Peninsula to Monterey ... Herds of elk and pronghorn antelope grazing in the meadowlands were like herds of cows they were so numerous. Packs of wolves hunted rabbits, deer, elk, antelope and other game ...

Historic Use of Fire

Even in 1542, Southern California's air quality was in question August 22, 2015 The San Luis Obispo Tribune

... During the 19th century, many recent arrivals from the East and Midwest thought the fires were deliberately started by Native Americans to facilitate their killing of wild game ... historical documents, indicate that Native Americans employed extensive burning of chaparral and shrub lands as a means of land management. They sought to turn the former into native grasslands to promote the proliferation of deer, antelope and small game...

Monterey Bay Area’s Native Amah Mutsun Seek Return to Lost Way of Life July 21, 2016 California, 90.3 Kazu

... The Amah Mutsun Tribal Band wants to restore ecosystems that once flourished here: from the deer herds that roamed the land to the medicinal plants that sustained the tribe...They may use controlled burning to maintain grasslands ...

Native Peoples' Relationship to the California Chaparral MK Anderson, JE Keeley - Valuing Chaparral, 2018

... many tribes of California ... natural fires with deliberate burning of chaparral to maximize its ability to produce useful products... Areas were burned in ways designed to create a mosaic of open grassland and recently burned, young and mature stands of chaparral with different combinations of species and densities. This management conferred on chaparral plant communities a degree of spatial, structural, successional, and biotic diversity that exceeded what would have been the case in the absence of human intervention... [the article contains many references to research about how this helped improve the deer herd] ...

Setting Fires and Restoring an American Landscape April 23, 2018 Illinois, New York Times

... For thousands of years, indigenous Americans ignited the landscape. Fire, they knew, brought bison and deer to hunt, and berries and tubers to harvest. European colonizers took these strategies and practiced them for centuries — but things changed in the early 20th century... The United States Forest Service started the Smokey Bear campaign, which portrayed all fire as destructive...

Changes brewing in woods won't help grouse (or deer) September 9, 2012 Minnesota, Minneapolis Star Tribune

The closing of six timber-consuming mills in Minnesota over the past five years has greatly reduced logging and -- if the trend isn't reversed -- will result in an older forest less productive for ruffed grouse and whitetail deer... if the forest products industry doesn't cut timber, there are no other management options. "It's the only tool we have to manage forest cover out there,'' said Schmid. It would be cost-prohibitive for the DNR to cut timber to manipulate wildlife habitat...

Estimating the Deer Population

The spreadsheet analysis and data for the graph above is available here. See page 167 of this paper for a discussion how the population was estimated in the graph above and of problems associated with previous historical estimates by CDFW of the deer population that contradict some of the agency's own historical data. CDFW estimated the population at 1.5 million in 1967. An estimate by William Longhurst and Aldo Leopold for the agency puts the 1947 population at at least 1.1 million, as noted in the graph above. After this estimate was published, an estimate of two million deer in California in the 1950s by the USDA was discovered. See page 2.

A two-year moving average of the buck harvest is used as a basis to estimate the long-term deer population in the graph above, a method commonly used for state population estimates. There were of few years of somewhat significant does taken near the peak population around the 1960s. Also used is the 1947 deer population study conducted by William Longhurst and Aldo Leopold who is considered by many to be the father of modern wildlife management. Note that the estimated kill to population ratio for 1947 reported in Table 1 is within the range of the modern period, so it is assumed this ratio has been relatively constant over time. Link to a paper explaining the population model.

On average since 1927 the doe harvest in California has been less than three percent of the total population. In one year, 1956, the doe harvest was 31.2 percent of the population.

In their 1921 report [page 23], the California Department of Fish and Game estimated there were 40,000,000 acres of deer country in the state and that assuming one deer per hundred acres would give 400,000 deer. The estimates are very rough, but in line with the graph at the top of the page. Mortality in that year was estimated as 20,000 killed by hunters, 30,000 killed by mountain lions, and with coyotes and disease added, the yearly mortality would be about 100,000.

The 40,000,000 acres of deer habitat in California equates to 62,500 square miles. Delaware currently targets its deer population at 40 deer per square mile. Applying this target to California would give 2.5 million deer, close to the number of deer estimated around 1960, suggesting a maximum carrying capacity for the state.

News Related to Historic Population

California drought may devastate wildlife populations May 5, 2014 San Jose Mercury News

... Gardeners may disagree, but the deer population in the state has been dropping steadily. In the 1960s, state officials say, there were more than 2 million deer in California. Now, there are only about 500,000. The drought will have an effect on them, too, as water sources become scarce and vegetation dies...

California deer face more challenges than ever September 21, 2013 California, San Francisco Gate, Tom Stienstra

... Deer numbers statewide are down 80 percent, a new invasive louse is causing deer baldness on the Peninsula and in parts of the Sierra foothills, and predation of fawns by mountain lions and bears is taking out a higher percentage of the herds than ever... The once-great deer herds of the Sierra Nevada, which migrated from the Sierra crest to wintering grounds in the foothills each fall, are gone. Heavy traffic on highways, new subdivisions ...

Deer Numbers, After Labor Day, a different outdoor world September 5, 2012 California, San Francisco Chronicle

... The outlook is bleak, especially in the Sierra Nevada. Deer populations are down by more than 80 percent from historical numbers, mountain lion predation has cropped fawn recruitment, buck-doe ratios are out of whack, and migration routes have been blocked in the Sierra to the point that the average deer lives in a five-mile radius...

Slaughter of Deer in the 1800s

Longhurst (1953) writes. 'The miners shot deer year-round for meat and hides and they altered the deer range by logging, burning, grazing and cleaning. Some of these changes ultimately benefited the deer but the immediate effect of settlement was a marked decrease in deer numbers. Thirty-five thousand hides were shipped by a single firm in 1880. One hunter killed over 300 in a single year and a second marketed 120; a third killed 93 at a time when deer were already scarce. They were marketed by the wagon load”

Deer Population in the 1940s

The population estimate in the graph above for the World War II period, 1940 to 1945, was adjusted up from the reported deer kill which declined significantly during that period. Many deer hunters were away at the war. This research indicates the herd was growing during this time. From California Fish and Game p. 456.... The 1940s became an active period for deer management in California (Dasmann et al. 1958): there were too many of them.

Deer became a “problem” of great magnitude, as 37 of 71 deer ranges surveyed during 1946–47 indicated that populations were out of balance with their habitats resulting in, “...depletion of range and waste of deer...” (CDFG 1947). Indeed, Storer (1932) described the problem in the early 1930s as represented by increasing damage by deer to agricultural crops as the deer population was apparently increasing. The increase in crop damage was attributed, in part, to more regulated harvest of deer with the initiation of game laws, aggressive control of predators, and the decreasing occurrence of fires on forested lands...

How Does CDFW Estimate the Deer Population?

CDFW declines to explain the details of its population estimation method. We filed a freedom of information request and got one small, undocumented spreadsheet that seemed to assume a downward future trend for the population. As with all state agencies, the annual deer hunt data is a major input into the population estimates. This peer-reviewed research article, starting on page 159, documents previous information on CDFW's website that significantly understated the historical deer population in California. After a presentation of the data on this site to the Western Wildlife society, CDFW removed this graph from their website although the graph is still available in the original research report and appears to have distorted some other estimates of the state deer population.

The graphic below shows the CDFW's estimate for the California population from 1991 to 2014 compared to the reported deer harvest. Some recent population estimates from CDFW do not track with the declining deer harvest data.