Natural curiosities Crappies are well known for their boom-and­ bust population cycles, says DNR fisheries research scientist Jeffrey Reed. The success of each year class depends on spring weather, the abundance of food at critical times in their life, and habitat conditions. Similarly, northern pike can experience boom-and-bust years, usu­ ally booming in response to exceptional spring spawning conditions. Northern pike will eat crappies and sunfish, but they prefer fish with­ out spines, such as minnows and suckers, and YN BARNES fish that are more cylindrical in body shape like SHERAL yellow perch. Fish populations are constantly Bullied Bluebirds. I have a bluebird house changing, and it is very likely that those crappies in my back yard, and every year when bluebirds you enjoy catching will return to levels you’ve sit on the house, robins chase them away. Why previously observed. do robins appear to dislike bluebirds? Dick Johnson, New Market Wild Rice Pests. Last August while harvest­ Robins bully bluebirds because bluebirds are ing wild rice in Itasca County, we found worms often at the bottom of the pecking order in about ½ to 1 inch long, off white, maybe 1/8 inch territorial battles, DNR wildlife educator Jan in diameter. The worms covered the mound of Welsh tells us. Bluebirds cope by nesting later wild rice as well as the bow of our ricing skiff. In in the season, sometimes as late as June, after 40-plus years of wild ricing we have always seen robins have settled into their own nest sites. this creature, but never such an intense mass. What are these worms? What is their life cycle? What part of the rice plant do they eat? Why were Missing Fish. I love ice fishing for crappies they so thick last year? and sunfish in a west-central Minnesota lake. I’ve Peter Sparen, Grand Rapids always caught decent crappies along with some sunnies up until about two years ago. I’m now These “worms” were most likely the larvae (cater­ lucky to catch a decent crappie every other time pillars) of a moth commonly called the rice worm I go out.The lake is definitely not overfished, but moth (Apamea apamiformis), says DNR insect the number of northerns has skyrocketed. Could expert Robert Dana. This is a well-known pest this be the reason for the lack of crappies? of wild rice. Adult moths lay eggs on the wild rice Dick Wegscheid, New York Mills flowers in mid- to late summer. The larvae that 6 Minnesota Conservation Volunteer emerge feed on the spikelet and kernels as they ing signs of the disease. Last winter there were develop, then eat their way into the stems, where numerous reports of bats flying during the day they overwinter until pupating in early June. As in surrounding communities. The DNR is very with many insects, populations can fluctuate interested in reports of bats seen flying during the strongly from year to year. day. Submit a report at mndnr.gov/reportbats. Maple Mystery. In early March I noticed patches of missing bark about as large as a man’s hand on many of the maple trees at my cabin in northern Minnesota.What could cause this? Jennifer Peterson, Clear Lake DNR forester Paul Dubuque suspects it could be the work of a yellow-bellied sapsucker. This woodpecker chips into bark to drink sap from trees, leaving holes that other animals can then enlarge. If your maples are relatively small and BARNES SHERALYN healthy, you could wrap burlap around the Odd Fox. Is there such an animal as a ring-tailed trunks or use tree guards to protect them. fox? Also, we saw a fox near Fargo that looked almost black.What was it? Harold Larson, Fergus Falls Winter Bat. One afternoon last January my husband and I observed a bat flying around our A species of animal called a ringtail lives in open covered porch. We are used to seeing bats the southern United States, but it’s not a fox. at night in the summer but not during the day in Minnesota has two fox species, red fox and gray winter. Is this just a confused little guy? fox, says DNR furbearer specialist John Erb. Red Ruth Jayson, Eveleth foxes occur in three color “phases”—the familiar red as well as silver and cross. The silver-phase Bats fly outside during winter, particularly on red fox is mostly black, but the tips of the hairs warm, sunny days, but this is not common. DNR are silver, giving it a frosty appearance on parts of bat expert Gerda Nordquist suspects you may its body. The cross-phase red fox has a lot of red have observed a bat suffering from white-nose and orange coloration but also a large amount of syndrome—a disease caused by a fungus that black on its legs, chest, underside, and sometimes thrives in the environments where bats hibernate. face. It may have a black X across the shoulders. It grows on their nose and wing membranes, Gray foxes can vary in color as with any species. causing the bats to arouse from hibernation. ask us Infected bats that leave hibernacula often die from exposure and lack of food. Sadly, the bats Send questions and daytime phone number to at Lake Vermilion–Soudan Underground Mine Natural Curiosities, 500 Lafayette Road N., St. Paul, State Park in northern Minnesota are show­ MN 55155-4046 or [email protected]. July–August 2017 7 .