Natural Curiosities

Q. During the holidays last year, I was shopping for bedroom slippers for my husband. I was amazed at the number of stores that were selling moose-hide slippers. Where are the hides coming from?

Lynne Bryant
Maple Plain

A. The leather used to make moose-hide slippers sold by L.L. Bean comes from Scandinavian moose harvested under the supervision of government wildlife managers to prevent starvation due to limited food supplies, according to a company consumer-affairs representative. Local people eat the meat. A spokesperson for Cabela’s said that company’s moose-hide slippers come from northern European moose that are hunted for meat.

Q. We have fed birds for more than 10 years and have always seen pine and evening grosbeaks at our feeders. Last winter we saw none. Our friends didn’t see any, either. Do you know why?

Donavon Wolff
Gilbert

A. Grosbeaks, crossbills, pine siskins, and redpolls winter in Canada, venturing south to Minnesota when their food supply dwindles, explains DNR nongame wildlife expert Carrol Henderson. Henderson suspects an unusually good food supply in Canada made for fewer birds at Minnesota feeders last winter.

Q. Some time back I took a picture of what I’m sure is an evening grosbeak, mainly because it was with a flock of about 20. Although it looks to be an immature with an overabundance of yellow pigment, it was much larger than the rest of the birds. What occurred, and how often does this happen?

Ron Johnson
Cloquet

A. "Looks like a goldfinch on steroids," wildlife expert Carrol Henderson says. It is indeed an evening grosbeak. The unusual coloring is a recessive trait, meaning it shows up only when a bird inherits a gene for it from each parent. The condition is uncommon but not rare.

Q. Today I swatted a housefly off my leg. On closer observation I saw about 10 mites attached to it. They looked like ticks except with no pattern on their backs. The fly’s entire abdomen was obscured by the rows of feasting parasites. What are they? Are they natural, or an imported insect to assist farmers?

Starr Quirt
De Graff

A. They’re naturally occurring hitchhikers called phoretic mites, says University of Minnesota entomologist Jeffrey Hahn. (Phoresy is a nonparasitic relationship in which one insect or arachnid species carries another.) The mites you saw were probably Macrocheles domesticae, which eat fly eggs. The fly most likely picked them up in the habitat where it hatched. If the fly had gone on to lay eggs, the mites would have gotten off to feed on the eggs.

Q. Last April after the ice had gone out we got renewed cold weather. One morning behind one of the radial gate water control structures at Sherburne National Wildlife Refuge ice had formed in circles ranging from 10 to 12 inches in diameter with a bigger buildup around the edges. Any thoughts from your experts would be appreciated.

Jeanne Holler
Zimmerman

A. The folks at the State Climatology Office suspect you encountered an example of a phenomenon called "pancake ice." Pancake ice forms in turbulent water when bits of slush form platelike clusters of ice. As the plates bump into each other they form circles with thick edges. The individual "pancakes" can be up to several feet in diameter.

Q. During the warm days last January, I saw the strangest congregation of cardinals in our back yard—six pairs hopping around the bushes and lower branches of trees. They displayed no hostility. I thought cardinals were very territorial. We have no bird feeder.

Benita Jatnieks
Minneapolis

A. Male cardinals are territorial during spring breeding season. However, in winter months, when they have no territory to defend, it’s not uncommon to see them gather peacefully.