Deer

The return of the white-tailed deer as a major game species in Iowa is a tribute to good landowner attitude and progressive management, research and enforcement programs. Likewise, responsibility for the future of deer in Iowa depends upon the cooperation of hunters and landowners, preservation of critical timber habitat, legislative support and continued professional management of the resource.

History & Population

White-tailed deer (Odocoileus virginianus) were reported to be quite abundant when settlers arrived in Iowa in the early 1800s. Although the clearing and cultivating of land for agriculture may have initially improved the suitability of the landscape for deer, uncontrolled exploitation for food and hides rapidly reduced deer numbers. 

By 1880 deer were rarely sighted in much of the state, and in 1898 the deer season was legally closed. By this time deer had been virtually eliminated from all parts of the state. In the early 20th century, reestablishment efforts grew the population, which again had to be controlled. 

Another reason that deer do so well in Iowa is that they are very mobile. Although many deer stay near the area where they were born, a significant number leave and travel to new areas before establishing a core area. These core areas may change seasonally with deer shifting between wintering areas and breeding areas. These movements allow deer to fill voids left open due to deaths and easily pioneer into new areas when habitat is suitable. High rates of movement occur during 2 periods of the year:

• The first is in the spring when deer move to their fawning areas. Many of last years fawns are forced to find areas of their own at this time. 
• The second period is in the fall during the breeding season. The breeding season begins in mid-October and runs through mid-January, although the peak of activity occurs during the first 3 weeks of November.

Habitat & Diet

Deer use many different types of habitat as long as the area provides adequate cover, including:

• Forests and wooded areas
• Brushy draws and fencelines
• Marshes and grassy areas
• Standing corn fields

Deer utilize almost all plants for food at one time or another during the year. Deer feeding habits can best be described as being erratically selective as deer will sample many plants while feeding but often utilize a single source of food for the majority of their diet.

Breeding & Family

The white-tail's ability to thrive in Iowa is likely the result of an abundant, reliable food source and a winter climate where snow depths rarely exceed 12" for a prolonged length of time. These factors combine to allow deer to come through the "winter bottleneck" in excellent condition.

The excellent nutrition also enables deer to have high reproductive rates. Some does are bred their first year, producing a single fawn, and many have 2 fawns each subsequent year. Deer in the wild can probably maintain these high reproductive rates until they are 10 years old. Past research in Iowa has found that 8 to 12% of adult does have 3 fawns.

Ongoing Management

Careful management of deer populations by man has also played a crucial role in allowing deer numbers to return to the levels enjoyed today. 

Management consists of carefully regulating the harvest, since hunting provides the only major source of mortality for deer today. Unchecked, Iowa's deer herd could grow at a rate of 20% to 40% each year. At this rate, deer numbers would double in as few as three years. 

With Iowa's abundant agricultural crops providing food, densities could potentially reach 100 or more deer per square mile before natural regulatory mechanisms would begin to affect deer health and slow the rate of growth. Deer numbers this high would cause economic hardship to Iowa's landowners as well as alter the natural vegetative community. Maintaining a deer population in balance with the wants and needs of the people in the state is a difficult task, but hunting is the only viable management option to achieve this goal.