Beavers attempt to plug up principal and emergency spillways and may even try to raise the elevation of the dam. The burrow will have many tunnels and chambers and always more than one entrance. Occupied burrows are easily spotted as the groundhog continually removes dirt from the den so that fresh dirt is visible on the surface of the dam. Controlling a groundhog infestation should commence in early spring when burrows are active and easy to find. If control measures are delayed other game animals may be damaged as during the fall and winter they may take refuge in the groundhog burrow.
Fumigation is one of the most affective methods of controlling groundhog population.
However, around buildings or in a high fire hazard area trapping or shooting may be a better approach. It has also been noted that a well cleared and mowed dam discourages inhabitation. Muskrats - The muskrat is a small stocky rodent with rich dark brown fur. Muskrats are chiefly nocturnal. Muskrat dens are constructed by burrowing into the banks of lakes and streams.