We have a cabin on a small lake in Cass County. Last spring the beavers girdled several large oak trees, dropped smaller oak trees, and totally stripped the bark off downed oak trees. They have not attacked oak trees with such a vengeance before, nor stripped the bark off the downed ones. Do they sharpen their teeth on oak trees? Are there nutrients in the bark of oak trees?
The beavers are stripping the bark to eat the soft inner layer. They'll chew down any kind of tree, says DNR wildlife educator Jan Welsh. Perhaps trees with softer wood, which beavers prefer, are harder to access or have already been harvested near your place. The hardwood oaks may be their next favorite dining option. To protect a tree from beavers, wrap 1/2-inch hardware cloth from ground level up at least 30 inches. Do not use chicken wire because beavers can chew through it.
A young queen bee or ant will mate shortly after leaving the hive, then proceed to build a home and lay egg after egg. If she only mates once, how is it that the sperm continues to be available and vital for years?
The queens of at least some native bees live less than two years. However, honeybee queens can live several years. Depending on the species, queen ants can live six years or more. Queen ants and bees have a structure, called a spermatheca, that stores sperm from their mating flight. As they lay eggs, they release a bit of sperm to fertilize them. Fertilized eggs develop into females. Occasionally some eggs are not fertilized. Those eggs develop into males.
In late October, we were camping near Togo, preparing for the rifle deer season. As the sun set, grouse started drumming. They drummed from numerous directions all through the night. Is this normal? Wouldn't they be attracting predators?
Drumming behavior exhibited by male ruffed grouse has been documented during every month of the year, says DNR grouse expert Mike Larson. Peak drumming during spring coincides with breeding season, when males are attracting females. During fall, males are primarily defending their territories against other males as juvenile grouse disperse across the landscape. Although drumming can attract predators, males protect themselves by using heavy cover, their natural camouflage, and vigilance.
While deer hunting in Chippewa National Forest, I sat in a stand of mature cedars. I noticed that there were no small seedlings anywhere in our hunting area. Is that because of the deer's appetite for cedars? How do cedars manage to regenerate?
The paucity of northern white cedars is connected with white-tailed deer's appetite. Deer love the taste of cedar, says DNR silviculture program coordinator Rick Klevorn. As deer range has expanded across Minnesota, cedar seedlings are having a harder time getting established. DNR foresters have tried a number of approaches to protect young cedars. Right now, in hopes of keeping some stands of cedar healthy, foresters are working to identify sites where regeneration efforts might be most effective. If seedlings survive long enough to grow at least partly out of a deer's reach, they can keep on growing.
Nuthatches are nesting in a couple of birdhouses I built. One of them sits on the roof and appears to be scratching it with its beak. Is it marking its territory, sharpening its beak, or what?
Keith and Joanie Krueger
According to DNR wildlife educator Jan Welsh, it's not unusual for nuthatches to rub dead insects on surfaces around their nests. The insects might contain chemicals that repel squirrels. If it wasn't holding an insect, Welsh says, it might have just been trying to clean its beak after a sticky meal.
While duck hunting last fall, a friend and I saw a large northern pike swimming with its head completely out of the water! The fish continued to swim in this strange way until I reached down and touched it, at which time it bolted back underwater. Any thoughts on this strange behavior?
This seemingly strange behavior is actually reported often, says DNR aquatic education specialist Roland Sigurdson. In most cases, the fish is trying to dislodge some irritation in the mouth or gills, such as a parasite, rock, or stick. Or, if the water had low oxygen concentrations, the fish might have been trying to force the most oxygen-rich (surface) water through its gills.