Uninvited Guests

On certain summer evenings out on the prairie you might hear what sounds like the howling of a miniature wolf. High-pitched and hysterical, a cry of "sk-sk-skreeee" slices through the wild grasses.

Measuring just four inches and weighing a single ounce, the furry source of this howling is the audacious little grasshopper mouse. Fiercely territorial and uncommonly bold, the males leave their burrows shortly after dusk, howl at the heavens to advertise their claims, and then swagger off in search of fresh meat.

While most mice dine happily on seeds, nuts and table scraps, the grasshopper mouse prefers to kill its dinner. Grasshoppers, appropriately, are a favorite prey. But this killer mouse also stalks mice, voles and kangaroo rats. Attacking from behind, it grabs its victim with its front legs and drives its incisor teeth into the brainstem. No playing around.

Those brown-furred critters scurrying through the grain fields, damaging crops and leaving tiny runways of felled grasses are more likely voles. Also known as meadow mice, voles have tiny ears, small eyes and bluntly rounded muzzles. And they are incredibly prolific.

All mice reproduce rapidly, but a single pair of sexually active voles averaging four young per litter will have 170 offspring in just six months. In the absence of predators (hawks, coyotes, snakes), winter kill, or diseases a vole population can quickly run rampant, nearing 10,000 animals per acre of ground in some fields.
    

There are also deer mice in the woods, white-footed mice in the thickets, and harvest mice in the lowlands.

Heather mice nest in pine trees. Zoologists have captured them by shaking tree limbs and catching the falling mice in wastebaskets.
   
Jumping mice are shy wetlands creatures. Surprise one on land and it will flee on its hind legs, weaving and bouncing erratically. On the water, you'll probably see it leaping away from you with frog-like jumps before diving underwater.


But if it's midwinter, you are indoors and have been seeing droppings in the house, the squeal you just heard was probably not a grasshopper mouse or a heather mouse or a pocket mouse, but a common house mouse.

Introduced by 16th century pilgrims in the holds of their Atlantic-crossing ships, house mice followed the progress of Europeans in the New World, traveling in wagons and rucksacks and saddlebags and trains and trucks and planes across the continent and back, occupying pantries from Maine to Malibu.

Grayish brown with a naked scaly tail, the pointy-snouted house mouse puts down 50 droppings a day, on average, and gives off 300 squirts of urine in between. Messy, ugly, and presumptuous, this uninvited guest inspires desperate measures.

Flat as a nickel pancake he squeezed under the back door, avoiding the window screening, steel wool and hardware cloth. Compulsive and near-sighted, he followed his nose to the stale cheese snag-tied to the lip of a snap-trap's pallet.

The sound you heard was his last gasp as the spring-sprung bar took his life away.