If the pond is completely iced over during the winter, there's no way for them to escape. If there was a drastic change in water levels, (i.e. higher water levels) the ice could have moved away from shore, leaving enough open water for them to escape. If not, and the water rose a couple of feet, they could have drowned in their dens.

Converesly, if the water level dropped, it could have frozen them in their dens, and they starved to death in the den.

Sometimes the water drops enough to leave a bit of a gap under the snow, and a mink will find it's way to the open area around the pond. They love muskrats and will kill them in their dens.

Also, because this winter was long, if there wasn't enough food in the pond for them, they could have starved to death.

Now, with the ice melting around the edges of the ponds or completely opening up, is the time that the males will move from pond to pond, looking for a mate.

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