Natural Curiosities

Last spring I got a tadpole for my tadpole habitat. It is now winter and it is still not a frog. Why didn't my tadpole turn into a frog?

Jack Kokkinen, Bloomington

It just might not be ready yet. Most Minnesota frogs metamorphose change into adults in eight to 10 weeks. Mink frogs, green frogs, bullfrogs, and some frogs native to other places overwinter as tadpoles. So keep watching!

If you get tired of your tadpole, be sure not to let it go in the wild. When animals are released where they are not native, they can cause problems for native species. If you have an amphibian or reptile you can no longer care for, call the Minnesota Herpetological Society, 612-624-7065, for information on its adoption program.

What has happened to jackrabbits in recent years? In the 1970s on Thanksgiving afternoon, my relatives would go on a jackrabbit hunt in Goodhue County. It always resulted in a number of jackrabbits harvested. In recent years, one can hunt all fall and not see even one.

Karl Brunner, Red Wing

It's a mystery to us. Gerda Nordquist, animal survey coordinator with the DNR Minnesota County Biological Survey, says the survey crew has found a scarcity of jackrabbits too, but nobody knows why. Conversion of prairies and pastures to cropland could be one factor, but that doesn't explain the drop where large areas of pasture and open land still exist. Other possibilities might be habitat change, hunting, predation, or pesticides. Readers with observations on jackrabbit numbers in Minnesota are invited to pass them along by calling the MCBS update line at 888-345-1730. Nordquist is also interested in hearing about observations, past or present, of badgers and spotted skunks.

We have a lot of black walnut trees. Is there a market for the nuts?

Erwin Eichhorst, Waldorf

Yes, says DNR forester Lance Sorensen. The DNR Forestry office in southern Minnesota buys some unshelled nuts for growing seedlings and for direct seeding on public land. Private vendors buy nuts for seeding on private land. Sorensen also knows of a buyer who purchases some Minnesota nuts for eating. For more information, call Sorensen at 651-345-3216 or 507-280-5569.

When I was growing up in Minneapolis in the 1960s and 70s, it seemed like squirrels hibernated all winter. Today's squirrels are out all winter. Is our climate making this happen? Or are the squirrels of today leaner, meaner, tougher?

Jim Lundeen, Minnetonka

Nah, they're just spoiled rotten. The boom in bird feeders over the past couple of decades is most likely why you see more squirrels in winter today than you did when you were growing up. Squirrels don't hibernate, but they do tend to become dormant in cold weather when food is unavailable. However, food is rarely a rarity these days, thanks to the abundance of bird feeders just waiting to be robbed.

Last winter the roads were white with road salt. Is this an environmental concern?

Jon Belisle, Maplewood

Road salt can harm water quality and plants and animals when it washes into lakes and streams, says Minnesota Pollution Control Agency scientist Keith Cherryholmes. The chloride in road salt is toxic to aquatic life in moderate to high concentrations. In low concentrations, it can interfere with reproduction and survival of young. Also, when dissolved in water, anticaking agents in the road-salt mixture dissociate and release a form of cyanide that is extremely toxic to aquatic creatures.

I'm fascinated by the gulls that follow tractors in the field, or fly around parking lots. What type of gulls are they? Where do they winter?

Jim Tessien, Mankato

Those big white birds are usually ring-billed gulls (named for the thick black ring near the tip of the bill). The behavior you observe is caused by that universal motivator: food. Gulls find worms and other invertebrates in the "farm-field buffets" turned up by plows. In parking lots, they are most likely after french fries and similar goodies. Ring-billed gulls winter as far south as Mexico and Cuba.

July Snow

Readers tell us it has indeed snowed every month in Minnesota (March - April Natural Curiosities). Reports of July snow include Biwabik (mid-1950s and 1969 or 1970), Brainerd (late 1960s), Currie (late 1940s or early 1950s), Ely (late 1920s), and Eveleth (1992).