White tailed deer are a familiar sight across Ontario, but what they eat is much more complex than it might appear. Their diet changes throughout the year as plants grow, mature, produce fruit and seeds, and eventually become dormant.
Deer are ruminants with a digestive system adapted to a changing natural diet. During spring and summer, they can select tender, highly digestible vegetation. During fall, energy rich natural foods become particularly important as deer build fat reserves. In winter, their diet shifts heavily toward woody browse such as twigs, buds and some evergreen foliage.
Understanding these seasonal changes helps explain what deer naturally need and, just as importantly, why putting out supplemental feed for wild deer is generally discouraged in Ontario.
What Do White Tailed Deer Naturally Eat?
White tailed deer are herbivores, but they do not simply eat grass.
They are selective browsers. Depending on the season and habitat, their natural diet can include tender shoots, leaves, forbs, flowers, woody twigs, buds, fruits, nuts and other available plant material.
Their food choices continually change as different plants become available and reach different stages of growth. Ontario's deer habitat guidance notes that deer particularly select highly digestible, nutrient rich portions of plants rather than consuming vegetation indiscriminately.
That ability to change their diet is an important part of how deer survive Ontario's dramatically different seasons.
Why Does a Deer's Diet Change With the Seasons?
A deer walking through an Ontario forest in June has access to very different food than one walking through the same forest in January.
During the growing season, fresh vegetation can provide relatively nutritious and digestible food. As temperatures drop and plants become dormant, those foods become less available.
At the same time, the animal's nutritional priorities change.
Summer includes growth, lactation and antler development. Fall is an important period for building fat reserves. Winter requires conserving energy while surviving on lower quality foods. Spring brings access to fresh new growth again.
What Do Deer Eat in Spring?
Spring represents a major transition.
After surviving winter on limited food and stored body reserves, deer begin finding fresh vegetation as temperatures rise.
Ontario guidance notes that deer eagerly seek cool season forage such as new greenery, legumes and fresh grass growth in early spring.
Tender new growth is particularly attractive because it is easier to digest than mature, fibrous vegetation.
Spring is therefore a period when improving natural habitat can provide deer with access to the vegetation their bodies are adapted to seek.
What Do Deer Eat in Summer?
Summer provides deer with considerably more choice.
During this period, deer may consume growing tips, succulent shoots, leaves, flowers, forbs and other tender vegetation.
They can also become highly selective. Ontario's habitat guidance explains that although green food is abundant during summer, deer seek high protein, high energy and highly digestible foods.
Summer nutrition is important because deer are using energy for several biological processes.
Young deer are growing.
Does may be nursing fawns.
Bucks are developing antlers.
Adults are maintaining body condition.
The surrounding habitat therefore plays an important role in providing a diverse selection of natural foods.
What Do Deer Eat in Fall?
Fall is an especially important nutritional period for white tailed deer.
As days shorten and temperatures fall, deer begin accumulating fat reserves that will help provide energy during winter.
Ontario guidance notes that deer seek higher energy and higher carbohydrate natural foods during fall. These can include cool season green plants as well as mast such as acorns and beech nuts where available.
The amount and quality of available fall food can influence the fat reserves deer carry into winter.
This is one reason healthy habitat containing a diversity of natural food sources is so important.
What Do Deer Eat in Winter?
Winter brings the biggest dietary challenge.
Across much of Ontario, deer rely heavily on browse during winter.
Browse includes woody twigs and buds from deciduous trees and shrubs as well as foliage from some conifers such as cedar and hemlock. Ontario notes that this winter diet is relatively low in protein and energy and high in fibre.
Deer also adapt behaviourally and physiologically to winter.
They reduce activity, food intake and metabolism, helping conserve stored energy. Their fat reserves accumulated during fall become an important part of surviving prolonged cold conditions.
This is why winter deer nutrition cannot be viewed simply as a question of giving them more calories.
Their entire body has adapted to the season.
Who Should Understand Seasonal Deer Nutrition?
Anyone who lives near deer habitat can benefit from understanding how deer feed.
Rural property owners may regularly see deer crossing their land.
Gardeners may discover deer browsing shrubs, vegetables and ornamental plants.
Woodlot owners can influence the quality of natural habitat available on their properties.
People who simply enjoy observing wildlife can also better understand why deer appear in different locations or feed on different plants throughout the year.
Understanding their natural behaviour is often more helpful than attempting to interfere with it.
Should You Feed Wild Deer?
This is where an important distinction needs to be made.
Learning about deer feed and nutrition does not mean that supplemental feeding of wild deer is recommended.
The Government of Ontario advises people not to put out food to attract wildlife and specifically discourages supplemental feeding of deer. Feeding can cause deer to gather unnaturally close together, increasing the potential spread of parasites and diseases. It can also increase human wildlife conflicts, habituation and deer vehicle collision risks.
Ontario's white tailed deer management policy also specifically identifies discouraging supplemental deer feeding as a strategy for reducing disease risks.
Why Can Grain, Corn and Pellet Feed Be a Problem?
This is particularly important because something that looks nutritious to us may not be appropriate for a wild deer's digestive system at that moment.
Ontario specifically warns that wild deer consuming large quantities of grain, corn or pellet feeds can develop serious health problems.
A deer's digestive system and its rumen microorganisms adapt to its current diet.
During winter, deer are naturally consuming large amounts of fibrous browse. Suddenly giving an animal access to large quantities of highly digestible carbohydrate rich food is very different from the gradual seasonal changes it normally experiences.
So a bag labelled for deer should not automatically be interpreted as something that should be placed outside for wild deer.
Products may exist for different applications, and users should always understand the intended use and applicable rules before purchasing or feeding them.
Why Is Disease Transmission a Concern?
Food piles can concentrate animals in a small area.
Under natural conditions, deer move through their habitat while browsing from many different food sources. A supplemental feeding location can repeatedly bring multiple animals to exactly the same place.
Ontario warns that these concentrations can increase the transmission of parasites and diseases, including concerns surrounding Chronic Wasting Disease, or CWD.
CWD is one of the reasons Ontario continues to discourage feeding wild cervids.
Preventing unnecessary concentrations of deer is therefore not simply about avoiding nuisance animals. It is also a wildlife health issue.
Where Should Deer Find Their Food?
Ideally, from their natural habitat.
Healthy forests, woodlots, meadows, edges and other suitable habitats can provide deer with changing food sources throughout the year.
Ontario recommends improving natural wildlife habitat rather than directly feeding wildlife. Native trees, shrubs and other vegetation can provide food while also contributing cover and broader ecosystem benefits.
For larger rural properties, habitat management can therefore be a more appropriate way to support wildlife than creating an artificial feeding station.
What Makes Good Deer Habitat?
Food is only one part of deer habitat.
Deer also need cover and access to water, and the relationship between these resources changes throughout the year.
Ontario's deer management guidance emphasizes the importance of having different habitat types available across the landscape. Deer move and shift their ranges seasonally in response to changing food and cover requirements.
Edges where different habitat types meet can be particularly useful because food and cover may occur relatively close together.
A healthy deer habitat therefore isn't simply a field containing something edible. It is a diverse landscape that provides resources across multiple seasons.
When Is Natural Food Most Important?
Natural food matters year round, but different periods present different challenges.
Spring provides important new growth after winter.
Summer supports growth, lactation and antler development.
Fall allows deer to accumulate fat reserves.
Winter requires deer to conserve those reserves while relying heavily on woody browse.
Rather than thinking about one ideal "deer food," it is more accurate to think about a sequence of natural foods that changes throughout the year.
What About Deer Feed Products?
Commercial products labelled for deer do exist, but the label alone does not tell you whether feeding wild deer is appropriate where you live.
Some feeds may be intended for managed or captive animals or other specific uses. Regulations, animal health considerations and intended applications can differ.
For wild deer in Ontario, provincial guidance is clear that supplemental feeding is discouraged.
If you're considering a feed product, first determine exactly what animals it is intended for and follow its label directions and applicable provincial and municipal requirements.
Are There Rules About Feeding Wildlife?
Yes, and rules can depend on where you are.
Ontario advises residents that municipalities may have bylaws prohibiting wildlife feeding.
For example, Ottawa's Parks and Facilities By law prohibits providing, depositing or leaving food that may be used by wildlife in a City park or facility.
Always check the rules applying to your particular location rather than assuming wildlife feeding is permitted everywhere.
How Can You Help Deer Without Feeding Them?
Focus on habitat rather than a feed pile.
Ontario recommends attracting and supporting wildlife through natural habitat. Native trees and shrubs can provide natural food and cover while allowing animals to continue normal foraging behaviour.
On properties where deer naturally occur, preserving appropriate vegetation and habitat diversity can provide benefits beyond deer as well. Birds, pollinators and many other wildlife species can use the same landscape.
It is a more ecological approach than teaching wild animals to associate people or buildings with food.
Common Deer Feeding Misconceptions
One common misconception is that deer need people to feed them because they look hungry during winter.
Deer naturally lose weight through winter and rely partly on fat reserves accumulated during fall. Their winter survival strategy includes reducing activity and metabolism.
Another misconception is that corn is automatically good for deer because they readily eat it.
An animal being willing to eat something does not necessarily mean that suddenly consuming a large quantity is healthy. Ontario specifically warns of health problems associated with deer eating large quantities of grain, corn or pellet feeds.
A third misconception is that one small feeding station cannot affect wildlife behaviour. Even relatively predictable food sources can encourage animals to return and congregate.
The 5 Ws of Seasonal Deer Nutrition
What do deer eat?
White tailed deer consume a changing selection of vegetation including tender shoots, leaves, forbs, flowers, woody browse, buds and seasonally available mast.
Who needs to understand deer nutrition?
Property owners, gardeners, wildlife enthusiasts and anyone living or working in areas where deer are common can benefit from understanding their natural feeding behaviour.
When does their diet change?
Throughout the year. Spring, summer, fall and winter each provide different foods and create different nutritional demands.
Where should wild deer obtain their food?
Primarily from suitable natural habitat rather than artificial feeding stations.
Why does seasonal nutrition matter?
Because deer physiology, digestion, behaviour and energy requirements are closely connected to seasonal changes in their natural environment.
There is no single perfect food for a wild white tailed deer.
Their natural diet is designed to change.
Spring brings fresh green growth. Summer provides tender leaves, shoots and other highly digestible vegetation. Fall is an important period for energy rich foods and building fat reserves. Winter brings a major shift toward woody browse while deer conserve energy and rely partly on those stored reserves.
Understanding that cycle is one of the best ways to appreciate how remarkably adapted deer are to Ontario's seasons.
And when it comes to wild deer, helping does not necessarily mean feeding. Ontario recommends improving natural habitat and allowing wildlife to forage naturally rather than establishing supplemental feeding sites.
Visit Ritchie Feed & Seed to explore feed products and speak with the team about choosing products for their intended use. https://www.ritchiefeed.com/
