Natural Curiosities

I found a small patch of foxfire in the leaves and decomposed wood on our property. I touched it, and it disappeared as it crumbled. How long does it take decaying wood to produce this phenomenon?

Sharon Babcock, Eagan

Foxfire is a blue-green glow given off by the mycelia (threadlike strands) of certain fungi that grow in rotting wood. Kim Coder, professor of silvics at the University of Georgia, estimates it can take up to four weeks for the mycelia to build up to maximum glow. They may keep emitting light for up to eight weeks.

To glow, fungi need to be of the right species. According to DNR forest health specialist Jana Albers, the bitter panellus (Panellus stypticus), found on hardwoods, is a good source of foxfire in Minnesota. Luminescence is most likely to occur when the decomposing wood is damp and when the temperature is in the high 70s. If you’d like to see foxfire, go for a hike in a hardwood forest after dark on a cloudy or moonless night in late summer or early fall.

I occasionally notice worm-casting-like structures near riverbanks. They are shaped like inverted cones, about 5 inches in diameter at the base, 3 inches at the top, and 8 inches tall, with a half-inch opening at the top. They are always in moist, gray, silty soil. I've never seen any activity or tracks nearby. Can you relieve my curiosity?

Tom Flemke, Owatonna

This sounds like a crayfish burrow, says DNR research scientist Gary Montz. He says some kinds of crayfish burrow into silty or loose soil, bringing up small pellets of soil and depositing them at the entrance in a "chimney" formation. The burrows usually go down to the water table.

What happens to the teeth of northern pike in winter? I have heard people say the fish lose their teeth in February and don't bite as often on bait. Others have said that the teeth in some fish appear to be loose at this time of year.

John Berklich, Hibbing

There's a long-standing belief, likely begun by ancient anglers in search of an excuse for their lousy luck, that northern pike lose teeth at certain times of the year. In fact, this is nothing but a fishy folk tale. According to DNR fish biologist Don Pereira, northerns may occasionally lose teeth in an unfortunate run-in with particularly tough prey or bait, but there's no evidence they do so regularly. For more on northern pike, see "For the Love of Pike" (May-June 2003).

In early March I witnessed a flock of about 20 blue jays bobbing up and down and making a loud, shrill, squeaking noise. I am 69 years old and have never seen blue jays act this way before. Is this a type of ritual?

Bob Bryan, Biwabik

It was probably the jay equivalent of a tailgate party. Gregarious birds, blue jays often gather in large flocks. As for the racket, jays and their relatives are good at reproducing sounds they hear. These noisy birds might have been mimicking en masse.

Why is the snapping turtle a species of special concern in Minnesota? Snapping turtles appear quite common to me. Also, is the concern limited to Minnesota?

Kevin Collison, St. Paul

DNR animal research coordinator Rich Baker says snapping turtles are both widely distributed and conspicuous. They were included in Minnesota's list of endangered, threatened, and special concern species when it was created in 1984 because harvest then was unregulated, and overharvest could cause the populations to quickly decline. Today DNR staff are working to change the statutes and rules governing commercial turtle harvest. Once changes are in place, Baker says, the DNR will consider removing the snapping turtle from the special concern list.

Where is the highest point in Minnesota? Where is the lowest?

Carl Neagoy, Brownsdale