March 2007

The DNR communications team works with agency experts to develop the weekly questions and provide the answers. This feature addresses current DNR issues, interesting topics, or the most frequently asked questions from around Minnesota.






It is not uncommon to find antlers lying on the forest floor in the spring. Why do buck deer, bull moose and other antlered species shed their antlers?

Annual cycles in deer antlers are related to the changing seasons. Deer have adapted their physiology and behavior to respond to seasonal changes, including antler growth and shedding. The environmental cue that regulates antler growth is the amount of day length, or photoperiod; the physiological cue is the hormone testosterone. Simply put, the changing day lengths are sensed by the eyes, which send this message via the optic nerve to the pineal gland that is located at the base of the brain. This triggers changes in hormone production. The declining day length in late fall and early winter causes a decrease in testosterone, which results in antler shedding. The actual process of antler shedding involves the formation of a thin layer of tissue destruction that forms between the antler and the pedicle, called the abscission layer. The degeneration of the bone-to-bone bond between the antler and the pedicle is considered to be the fastest deterioration of living tissue known in the animal kingdom.

- Michelle Carstensen Powell, Wildlife Health Program Coordinator


Every spring the DNR imposes burning restrictions for counties throughout Minnesota. Why are they needed and what is their purpose?

The DNR issues burning restrictions to help reduce the potential for personal property damage and injuries resulting from the large number of spring wildfires. A majority of these wildfires occur as the result of burning vegetative debris from yard cleanups. As the snow melts, the dead, dry vegetation becomes an instant fuel source. Any accidental or managed fire that escapes control could spread quickly and uncontrollably across the landscape, including residential areas. The restrictions are set to coincide with this time of the year, when the fire potential is the highest and historically when most fires occur in Minnesota. Burning restrictions may also be implemented at other times of the year during drought conditions, for example. Restrictions typically last 30-45 days.

- Jean Bergerson, Minnesota Interagency Fire Center information officer


Water quality is important to all of us. Are there any simple things people can do to help keep our lakes, rivers and wetlands healthy?

Removing trash along a riverbank, lakeshore or from a wetland is that step in the right direction. Through the DNR's Adopt-a-River program, people can sign up to "adopt" a section of a lake, river or wetland to ensure its long-term health through annual cleanups. Volunteers choose their own site from shorelines that have not yet been adopted. The program supplies "how-to" assistance, free rubbish bags, gloves and recognition after a reporting of cleanup results. Between 1989 and 2006 more than 2,200 cleanups have been completed by more than 66,000 volunteers in 64 Minnesota counties. They have removed about 4.8 million pounds of rubbish from 7,500 miles of Minnesota's public waters, utilizing 226,000 hours of effort. Visit the Adopt-a-River program.

- Paul Nordell, Adopt-a-River Program coordinator


With spring here, wildlife is beginning to become more active, and in some cases, perhaps too active. There have been reports of nuisance squirrels finding their way into homes. How can homeowners deal with these critters?

The best method for dealing with squirrels is prevention. Remove trees or over-hanging branches and close off any external openings that might allow access to a home or other structures. Repellents such as mothballs or ammonia soaked rags are an option to help convince a squirrel to leave. However, care should be taken to ensure that human occupants are not affected. Once the squirrel is out, one-way openings, such as an 18-inch section of 4-inch diameter PVC pipe placed at a 45-degree angle pointing toward the ground, can help keep squirrels from returning until the opening can be sealed permanently. State statute does permit the use of lethal removal methods - traps or shooting - but before pursuing this option, homeowners should check local ordinances. Trapping squirrels and relocating them to other areas is not recommended because they typically do not survive.

- Bryan Lueth, DNR urban wildlife specialist


DNR Question of the Week Archive