PURPOSE:  To investigate the food requirements of deer in winter.

MATERIALS: Field -- Suitable winter clothing, snowshoes or cross-country skis, back pack, plastic garbage bag, watch, map & compass, knife or pruning shears, pencil, index card.  Lab -- platform balance.

INTRODUCTION:  In northern environments, deer often have a very difficult time coping with winter. They have small hooves and legs which are too short for deep snow.  If the snow pack is 40-50 cm (16-20 in) deep, the deer's body may rest on the snow!  Deep snow causes stress on the animal due to heat loss and decreased mobility.

The cold weather of winter may cause a 70 kg (150 lb) whitetail deer to burn as much as 6000-7000 kcal/day.  To keep its body temperature regulated, the deer must eat between 3-6 kg (7-14 lbs) of green forage per day.  The harder the deer has to work to find forage, the more it must eat. 

The kinds of plants that are useful as food to deer (deer browse) are determined by the anatomy of deer.  Deer do not have any incisors (front teeth) in their upper jaw.  As a result, they tend to shred plant material, rather than make a clean cut like rabbits that possess upper and lower incisors.  Deer prefer to eat the tips of plant stems.  They can reach up to 2 m (6 ft) from the ground.  Hunger sometimes drives deer to eat any food, even tree bark, just to fill their stomachs.  These "stuffer" foods offer no nutritional value.

Many people think that the best areas for deer are deep in the heavily canopied mature forests.  However, deer are often seen at the border between forest and field, an area called edge or ecotone.  The ecotone has a wide variety of mixed field and forest vegetation.

In this activity you will act as deer feeding in a woods or ecotone habitat.  After learning to recognize the plants that deer eat, you will venture out on snowshoes or cross-country skis to a variety of possible deer habitats.  You will then collect as much deer food as you can in 30 minutes.  In the lab, you will relate the amount of food you collected in this limited time to what an average deer could find and eat in a single day.

PREDICTION: Use what you know about deer and the plants in your area to make a prediction.

1.  Is more deer browse available deep in the forest or at the edge of the forest?

PROCEDURE: Work with a partner. Be sure to use a map and compass in rural or wilderness areas.

A.  Locate a study area inside a forest or at the edge of a forest community.

B.  On an index card, describe the physical characteristics of the area you are going to study. Determine the average snow depth in the area.  Estimate the height of the lowest branches on the trees or shrubs. 

C.  With your partner, collect as much deer food as possible in 30 min as follows: 

D. In the lab, list the plant species you collected on the data sheet.  Separate the plant material into an edible group and a stuffer group.  Weigh the amount of plant material in each group. Record and share your data with the class.

E.  When you are finished with your study, don't waste the plants!  Spread them on the snow or on stumps so that the deer can benefit from all your hard work.

CONCLUSIONS:

2. What plants were most available in your study site?  Were they edible or stuffer foods?

3. Did you see any signs of deer browsing?  If so, on what plants?

4. Using class data, what type of habitat contained the most food for deer?

5. Using class data, what type of habitat contained the best quality food for deer?

DISCUSSION:

6. If you were a deer, would you have starved or survived on the day you collected deer browse?  Use the information in the Introduction and your data to support your answer.

7. How is the quantity of deer forage related to the diversity of plants?  Use class data from the forest and the forest edge to explain your ideas.

8. How did snow depth and the height of the lowest branches above the ground affect the quantity of deer food collected by the class?  Use class data from the forest and forest edge to support your answer.

DEER BROWSE DATA SHEET

Type of Study Area:    Forest    Edge            Time Begin:____________
Location of Study Area:_____________________     Time End:______________
____________________________________________     Elapsed Time:_______min
Snow Depth:_______________cm    Height of Lowest Branches:_____________m
Plant Species Collected:
______________________________________    Edible Plant Weight:_________g
______________________________________    Stuffer Plant Weight:________g
______________________________________
______________________________________
______________________________________

CLASS DATA TABLE: