An Excerpt from Jim Conrad's
Naturalist Newsletter of April 24, 2005

issued from California's Sierra Nevada Foothills

A CALIFORNIA MOUSE

Yesterday while walking past the garage I found a dead mouse on the ground, clearly left there by one of my friends’ housecats. At first I thought it was a White-footed Mouse like those with whom I coexisted more or less peacefully for years in Mississippi, but then I started noting some differences. It seemed a bit larger than those and –- though White-footed Mice have long-enough tails –- this one’s tail was super long. I checked my mammal fieldguide and, sure enough, though White-footed Mice occur in about the eastern two-thirds of the US, they don’t make it to here. What I had was a California Mouse, PEROMYSCUS CALIFORNICUS, a member of the same genus as White- footed Mice. You can see a California Mouse, see its limited distribution and read all about it at http://wotan.cse.sc.edu/perobase/systematics/p_calif.htm

Most people just don’t know what an interesting world of native mice there is out there. House Mice have given our native mice a bad name. House Mice were introduced into the Americas at about the time of the American Revolution, from Eurasia, so they are the mammalian equivalent of crabgrass. Like crabgrass, they thrive where people concentrate making messes.

According to Burt & Grossenheider’s “A Field Guide to the Mammals,” in North America north of Mexico there are about 16 species of regular mice, as well as 5 species of harvest mice, 2 of grasshopper mice, 21 of pocket mice, 2 kinds of kangaroo mice, 4 jumping mice, and then about 20 kinds of voles, which most people would think were mice if they saw them, and finally there are numerous native rat species, which are just as interesting and who also get bad press because of their introduced European cousins.

Our native mice are highly sophisticated beings with very complex social behavior and specific habitat requirements. The above site describes California Mice as “...generally slow and passive with a decreased tendency to bite. In addition, it has its long, dense, fine fur effective against cold, but ineffective in shedding water.”

The page goes on to say that California Mice are good climbers and exceptional gnawers. Males fight one another displaying a lot of jumping and making a “mewing call.” Females are exceptionally attached to their nests and will defend it.

It happens that I find this cat-killed mouse during a week when there’s a good bit of discussion about Wisconsin’s idea of offering a hunting season on feral cats, in order to cut down on their destruction of wildlife. There’s a good bit of information about the effects of wandering housecats on wildlife at www.owra.org/cateffect.htm

One study reviewed at that site came to the conclusion that each year a typical domestic cat kills on the average at least 26 birds in urban areas or 83 in rural areas. Just in the state of Virginia that comes to over 26,000,000 housecat-killed birds.

I’ve heard a lot of people say that cats don’t kill wildlife when they’re well fed.

That’s wrong.

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