Species-Specific Management (SSM)

Muskrat

The muskrat (Ondatra zibethica), also known as the marsh rabbit, is a valuable wildlife resource, both in economic and aesthetic terms. It is one of the most valuable fur-bearing mammals in North America as noted by the number of pelts collected each year. The meat of the muskrat is also consumed in many areas, and is considered to be quite delicious. The muskrat is commonly found along banks of large streams and rivers of the southern Appalachian and within open areas of wooded marshes. Occupying a wide variety of habitats, the muskrat is subjected to many environmental pressures along with heavy exploitation by trappers. It, however, seems to tolerate these conditions with a certain amount of resiliency. It seems to limit it own population size, never becoming very abundant. They migrate and experience other limits. The first set of items below deals with increasing the population; the last items examine some of the problems that muskrats cause, and some possible solutions.

1. The muskrat prefers still or slow-moving water, but can tolerate polluted water. The habitat must have the right kinds and amount of food, and water that is in a range of fresh or brackish. The muskrat will, however, choose food requirements over water suitability, if both are not available.
2. Common predators of the muskrat are: mink, red foxes, horned owls, snapping turtles, and northern pike. Some selective reduction of predators of the muskrat may be necessary to increase fur yields, but it is advised to have a high population of minks where there is a high population of muskrats. The mink serves as an excellent indicator species for the muskrat.
3. Food preference of the musk in marshy habitats include:
   • Cattails
   • Pickerelweed
   • Hard and softstem bulrush
   • River bulrush
   • Marsh smartweed
   • White waterlilly
   • Sedges
   • American lotus
   • Black willow
   • Duck potato
   • Reed cane
   • Wild rice
   • Water milfoil
   • Coontail
4. Overall population value of vegetation types for the muskrat (from Illinois; a similar list is estimated for the northern part of the Appalachians):
   • River bulrush
   • Cattails
   • Marsh smartweed
   • Hardstem bulrush
   • Reed cane
   • Sedges
   • American lotus
   • Duck potato
5. The prevention of high populations of muskrat "eat-outs" of bulrush is crucial to managing a population. A solution to this is to make sure there is an adequate harvest of muskrats during the fur season.
6. Muskrats cannot be stock-piled as a fur-bearing resource.
7. Pay attention to the cyclic fluctuations of the muskrat population. Look at it as a result of the amount of crowding which the muskrat will tolerate.
8. The stocking of muskrats into a new area is not recommended. The effects of introduced species can never be fully predicted, even though they may not seem a threat. Concentrate efforts on restocking of animals into areas that have had muskrat populations depleted or exterminated. If stocking is chosen (and it is rarely recommended), start with enough animals that may breed successfully, say 12 per 100 acres of suitable habitat.
9. The stocked animals must be in good health and must be of the same subspecies of the closest natural muskrat population to where they are to be stocked.
10. Providing suitable shelter material for the muskrat is necessary. Two types of shelters are used. One is lodges built from vegetation that is in the marsh, while the other is a burrow in the banks with an underground entrance. The bank must be high enough (about 2 or 3 feet) above the water level for the muskrat to nest in it. During flood situations, the muskrat will normally abandon these sites. These burrows can also be very intricate, some going out 100 feet from the bank. This calls for special consideration of structures that are nearby.
11. An important plant for the muskrat is the broad-leaved cattail. It is present in shallow water and will be killed out at water levels of 3 to 4 feet (or after grazing and less flooding). If the level of the water is manageable, then the exposed bottom of some areas may need to be flooded by fall to allow for the germination of the cattail seeds. These seeds germinate best during the late summer. Hand planting can be done in special circumstances where the cost will not be too much.
12. You may want to protect the bank's vegetation as well. It not only helps the muskrat, but is a good land-use practice as well. Protected muskrat territory along creeks may be accomplished by fencing out livestock.
13. Diked marshes are 6 times more productive than undiked marshes.
14. Muskrats can help maintain excellent open-land waterfowl habitat.
15. Prescribed burning can be an effective management tool to get desired fool plants (consult public agencies for laws and policies).
16. During the colder season, high nutrient food is very important.

Damage related issues:

1. Muskrats seldom raid crop fields when there is "natural" vegetation available to them. These vegetation types must be within 50 or 100 yards of their nests to be effective in preventing corn field raids.
2. Make sure that the managing technique that you use is legal.
3. When reduction is desirable, the common method is trapping. When live trapping is not feasible, the only alternative is the conibear trap. You must be extremely careful in setting these traps so as not to capture other desirable species, such as waterfowl. When trapping is no longer necessary, be sure the traps are removed or sprung.
4. Systematic destruction of burrows can be effective.
5. Wire mesh (e.g., placed within dams) can be more effective in preventing muskrats from entering areas rather than reducing the population.
6. Sheet-iron hanging covers are effective for tile drains, allow for water flow, and keep out muskrats.
7. Consult the U.S. Natural Resource Conservation Service (formerly Soil Conservation Service) for instructions for muskrat-proofing dams and banks.

References

Bellrose, Frank C. 1950. The relationship of muskrat populations to various marsh and aquatic plants. Journal of Wildlife Management. 14(3): 299- 315.

Cartwright, B. W. 1946. Muskrats. Duck Production, and Marsh Management. Transactions of the North American Wildlife Conference. 11: 454-457.

Emerson. F.B. 1961. Experimental establishment of food and cover plants in marshes aeated for wildlife in New York State. New York Fish and Game Journal. 8(2): 130144

Errington, P. L. 1961. Muskrats and Marsh Management. Stackpole Publishing Company, Harrisburg, PAt 183 p.

Giles, Robert H. Notes on Muskrats. Wildlife Resource Management Systems. VPI. 1993.

Hensley, AL. and H. Twining. 1946. Some early summer observations on muskrats in a northeastern California marsh. California Fish and Game. 32: 171-181.

Krummes. W.T. 1940. The muskrat: a factor in waterfowl habitat management. Transactions of the North American Wildlife Conference. 5: 395-404.

Lewis. Mark B. 1976. A Short Report on the Muskrat. Department of Fisheries and Wildlife Science. VPI and State University, Blacksburg, VA. 14 p.

Mathiak, H.A. and A.F. Linde. 1956. Studies on level ditching for marsh management. Wisconsin Cons. Dept. Tech. Wildlife Bulletin. No. 12. 48 p.

Metzar, R.G. and D.A Whartan. 1968. Planning the management of Maryland wetlands. Proceedings of the Annual Conference of the South Eastern Association of Game and Fish Commissioners. 22: 68-82.

Penfound. W.T. and J. Schneidan. 1945. The relation of land reclamation to aquatic resources in southeastern Louisiana. Transactions of the North American Wildlife Conference. 10: 308-318.

Takos, M.J. 1947. A semi-quantitative study of muskrat food habits. Journal of Wildlife Management. 11: 331-339.

A contribution of Matthew L. Brestel, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061

This Web site is maintained by R. H. Giles, Jr.
Last revision January 17, 2000.