All About the Mule Deer
It's a good time to talk about DEER on the Pajarito Plateau! Today, there are perhaps 300,000 mule deer and the less-common white-tailed deer combined in our state. Food, water, and productive cover govern the numbers of deer. Harsh winters may force deer to lower elevations, while mild summers will place them at timberline.
Suburban areas invite deer in with resources that are more easily accessible than in mature woods. Grassy parks, blooming gardens, and ornamental plants provide good nutrition, leading to excellent physical condition and higher reproductive rates of deer. Safe from hunting and predators, and sometimes fed intentionally, deer become habituated to people and occupy public and private spaces.
For some, the presence of deer is a welcomed wildlife viewing opportunity, while for others it means disturbed garden beds, a threat of disease, and road hazards. Competing attitudes towards deer lead to differing perceptions of severity and frequency of conflicts. Over the next month we will take a look at several issues regarding living with deer on the Pajarito Plateau, and how we can prevent conflicts, as well as support a healthy and safe living for these beautiful creatures.
Winter feeding of mule deer can lead to disease transmission, predation, and other negative effects.
Human compassion makes people want to help mule deer with winter-feeding programs. Winter feeding of mule deer creates artificially high concentrations of animals, leading to increased risks, including disease transmission and predation. Human disturbance can reduce a mule deer's body condition and increase their energy use, which can impact their survival and reproduction. Winter-feeding also has the potential to disrupt both winter foraging activities and migratory patterns. Unlike elk, mule deer are highly selective foragers, at least in part, due to their specialized digestive system. Winter-fed mule deer often die with full stomachs due to their inability to adapt to rapid changes in type and abundance of feed.
As mule deer learn the locations of feeding stations, they continue to visit these sites, may fail to recognize the need for migration, and then share the information with each successive year’s offspring. Winter-feeding locations generate artificially high animal densities at feeding sites. These high densities of animals provide ideal opportunities for the transmission of diseases and parasites. Winter feeding in areas highly populated by humans may create significant liability issues in terms of attracting predatory animals such as mountain lions, and can attract deer into high traffic areas, causing an increase in vehicle accidents.
Both proponents and opponents of winter feeding believe they have the deer’s best interest in mind. We must focus on the sustainability of the mule deer population for generations to come – not just one season. Changing nature by winter feeding is a complex matter involving numerous issues. At best, winter feed of mule deer is only successful in making people who are compassionate about wildlife feel better and seldom are any benefits of winter feeding realized.
Mule deer have several strategies for surviving the winter, including:
Conserving energy - Mule deer limit their movement and physical activity to conserve energy.
Finding shelter - Mule deer seek shelter from the wind and cold in thickets, under evergreen trees, and in other areas with lots of vegetation. They also look for areas with snow that's not too deep.
Migrating - Mule deer may migrate to a "winter range" or "deeryard" that offers protection from the elements, good browse, and thermal cover.
Adapting their diet - Mule deer may eat twigs, bark, and other woody plants when their preferred food sources are scarce. They also use their antlers to brush away snow from their food sources.
Withstanding cold temperatures - Mule deer are well-adapted to cold climates and can withstand temperatures as low as -40°F. Their thick fur helps insulate them.
Learn more about Understanding Mule Deer and Winter Feeding. Visit the Living with Wildlife website to learn more about the animals of the Pajarito Plateau.
DEER Fun Facts
- Their sense of smell is 1000 times stronger than a human's. They can smell a person up to half a mile away and can detect water up to 2 feet underground.
- A mule deer's eyes are located on the side of its head, providing 310 degrees of vision. Mule deer have better night vision than humans and can spot predators up to 600 meters away.
- Antlers can grow up to 1/4 inch per day. Antler growth stops in August and then the antlers harden. Bucks will use their antlers to fight each other for a doe when in rut. Antlers are then shed after the mating season and re-grow in the spring.
- Mule deer have no upper teeth, only a hard palate.
- When startled, a mule deer will bounce away by pushing all four hooves off the ground at once. This is called "stotting." Mule deer can jump 2 feet high and up to 15 feet in distance. Mule deer can run up to 45 MPH.
Living with Mule Deer Fawns
Every year, Los Alamos County and NM Game & Fish receive numerous phone calls from the public concerning abandoned newborn fawns. In almost every instance, the fawns have not been abandoned and are waiting for the doe to return to nurse. People who find newborn fawns should never approach or pick them up—doing so dramatically decreases the probability that fawns will survive.
"Hiding" Behavior
Shortly after birth, mule deer fawns exhibit hiding behavior to avoid detection and maximize survival. Newborn fawns are licked clean by the doe to minimize scent and have a spotted coat to help camouflage them. Newborn fawns spend more than 95 percent of their time hiding. Fawns are typically alone, or within a few meters of their twin, during most of the day for the first week of life. They only stand a few times each day when the doe comes to nurse them. Once nursed, the mother nudges the fawn back to the ground and leaves the immediate area— usually remaining just a few hundred meters away. This pattern will continue for up to 3 weeks. By this time the fawns are mature enough to keep up with their mother and able to race out of real or perceived danger.
I’ve found a deer fawn (baby deer). What should I do?
Under most circumstances, the best thing a person can do is to immediately leave the area to avoid creating any additional disturbance near the fawn. Approaching or handling newborn fawns increases their stress level and threatens their survival.
The fawn was alone, with no mother protecting it. It is so small and helpless and it doesn’t even move when I approach it. Does it need help?
No, the fawn does not need your help. The fawn is well camouflaged and has very little odor, which helps it hide from predators. Fawns instinctively lie motionless when approached by a potential predator. A fawn's heart rate will also drop dramatically as another way of protecting itself.
It looks hungry, should I feed it?
People should never feed anything to a fawn. Just like an adult deer, fawns have very specific nutritional requirements and improper nutrition will make the fawn sick and may lead to its death.
My children touched or moved the fawn and I’m afraid the mother won’t take it back - what should I do?
The doe-fawn bond is very strong. A mother deer will not avoid her fawn if there are human or pet odors on it. Fawns are rarely abandoned, except in extreme cases where the fawn has defects that will prevent its survival. If moved, the fawn should be placed in or next to natural vegetation near the location where it was found to provide cover and protection. The doe will avoid the area until the disturbance has passed, after which she will search for the missing fawn. If more than 24 hours have passed, the fawn may need attention from a wildlife rehabilitator. In this case, call NM Game & Fish at 888-248-6866 (toll-free) or 505-476-8000. In an emergency, call 9-1-1.
Why we don't want to feed the deer: A Three-Part Series
Part 1: Does the forest support the deer population following a wildfire?
The natural pattern of recovery after a wildfire is referred to as “ecological succession.” This is the process whereby the land, plants, and wildlife move through various ecological stages to return to a state of relative stability. It’s like hitting the “reset” button on the life cycle of a forest.
Low-intensity fires burn close to the ground, “cleaning” and thinning the forest by removing thick and flammable vegetation from the forest floor. High-severity fires burn with high heat, climb into and remove the tree canopy, and can scorch the soil and tree roots, causing a more severe impact on vegetation and wildlife. More light reaches the forest floor post-fire, and fire-adapted plants regenerate.
After a fire, burned forests can be lush with shrubs and other vegetation that deer favor as summer forage. Deer generally prefer burned areas for about 20 years post-fire, which is the time it takes for the forest to move beyond the initial regrowth stage. Burns can create a win-win for deer: more food and less risk of being detected by a predator.
To learn more about wildfire in the Jemez Mountains and its impact on the ecosystem, visit the Valles Caldera Wildland Fire webpage.
Part 2: Jemez Mountain forest restoration, wildfire, and habitat selection by female mule deer
A brief history and the necessary response...
Decades of fire suppression, logging, and overgrazing have led to increased densities of small-diameter trees which have been associated with decreases in biodiversity, reduced habitat quality for wildlife species, degraded foraging conditions for ungulates [such as mule deer, elk, and sheep], and more frequent and severe wildfires. In response, land managers are implementing forest restoration treatments using prescribed fire and thinning to mitigate the risk of catastrophic wildfires and improve habitat conditions for a variety of wildlife species.
[source: Science Direct - link below]
Studies and observations...
In 2022, eleven years after the Las Conchas Fire, National Park Service staff began revisiting [burned] plots in the Valles Caldera National Preserve and graduate students from the University of New Mexico are analyzing the data to better understand post-fire ecological succession. This project is crucial in helping land managers understand the ecological role of fire and its long-term effects on the landscape in order to better preserve and restore this fire-adapted landscape.
source: NPS - NPS Article on Vegetation Recovery
Ecosystems are dynamic, with plants and animals responding to disturbances like wildfires and habitat loss. Researchers are monitoring the behaviors of four large mammal species - mountain lions, black bears, elk, and mule deer - to determine how ecosystem changes can impact their habitat preferences. How these large mammals respond to ecosystem changes over time will help park managers implement restoration treatments that mitigate wildfire risk and enhance habitats.
During this study, researchers captured and monitored 34 mule deer. The mule deer largely selected forest areas burned by prescribed fire and generally avoided wildfire-burned and thinned areas when they were [younger than] 5 years old. However, mule deer strongly selected thinned areas [at and over] 5 years old.
The next phase of the project is to analyze changes in habitat selection of these large mammals across a broad area of ecosystem disturbance. This analysis will help inform future decisions regarding forest management, wildfire mitigation, and habitat restoration at Valles Caldera National Preserve and beyond.
source: NPS - NPS Article on the Large Mammal Project
To learn more about research done by Science Direct in their Forest Ecology and Management study, as well as additional documented studies around wildfire in the Jemez Mountains and its impact on the ecosystem, mule deer, and black bears, click here: Science Direct Full Article
Part 3: What's wrong with feeding the deer?
Two important things to highlight have both ecological and physical consequences.
Deer support a healthy ecosystem…
Well-intentioned people will feed mule deer, under the assumption it will ensure their survival out of concern for lack of food sources. Unfortunately, feeding of any kind causes more harm than good to mule deer and only furthers their decline. Mule deer are adapted to their environment and specifically to the plants they rely on to survive. Throughout the summer they eat highly nutritious plants to build up their fat stores. Through the winter they eat less overall and transition to eating woody plants that are less nutritious while they utilize their fat stores for energy and survival.
Deer are browsers and will feed on tree bark, shrubs, grasses, forbs, flowers, and other nutrient-rich plant materials. Some of these plants rely on animals like deer and won’t germinate unless they pass through the digestive tract of an animal. The deer go to where food is readily available, which in a healthy ecosystem is the forest that provides them the food and nutrients they need. When fed by humans, deer will become lazy and stop foraging for food and doing their part in the life cycle of these plants, causing them to dwindle and become scarce. This negatively impacts the forest's healthy ecosystem and how it supports all the wildlife of the forest.
Deer have specialized digestive tracks…
Unlike elk, mule deer are highly selective foragers due to their specialized digestive system. Mule deer digestive systems contain specific bacteria that help break down only the plants they are meant to eat and are adapted to. The bacteria adjust slowly to match their diet through each season, and in the winter their gut contains the appropriate bacteria to digest only their winter diet of woody materials.
Any human-provided food sources, including hay, apples, corn, etc., are simply not digestible and cause an abundance of lactic acid, acidosis, dehydration, and ultimately death. Fed mule deer often die from starvation with full stomachs of food they cannot digest.
In August, mule deer bucks exhibit a variety of behaviors, including:
Feeding
Mule deer eat a lot to keep up with the energy needed to grow their antlers. They eat grasses, forbs, and other broad-leafed vegetation, such as bitterbrush, dandelion, mountain bluebell, and clover.
Bedding
Mule deer bed early and feed late. They often bed in the open under a single tree, scanning for danger.
Antler growth
Mule deer antlers are still in velvet in August, and the velvet makes them appear larger than they will be after the velvet is shed. Bucks' antlers begin to harden at the end of August, and they strip their velvet around the 15th.
Group structure
Mule deer bucks are often in bachelor groups with other bucks of the same age. Young bucks may be with does or with a group of adolescent bucks.
Elevation
Mature bucks tend to prefer higher elevations because they are cooler and have fewer bugs.
By September Mule Deer bucks are…
- Rubbing off and Shedding their velvet and summer coats in early September
- Continue to hang out in bachelor groups for a few weeks
- Spend more time in thicker areas, feeding and browsing longer in cover
- Actively trying to gain fat reserves to prepare for winter starvation
- Larger bucks will start to break away from the group and be off on their own or in small groups by early October
- Often bed close to where they feed