May 13, 2008

The Deer Mouse Surge

Almost every fall I face an attempted migration by deer mice (Peromyscus) into the garage, which connects with the basement and thus the rest of the house.

I don't like them in the house because of (a) the hantavirus risk and (b) the annoyance of hearing mice in the walls when I am trying to go to sleep.

The cats used to take care of any mice who made it into the main house, but M. and I are currently cat-less. And the basement does not connect directly with the upstairs.

So I lay traps. But this year, the traps are catching mice in May. Perhaps connected with this mouse surge, M. and I have seen several dead mice, unmarked by predators, lying around near our house and the guest cabin.

Some quick Web research leads me to think that while the deer mouse population fluctuates in the course of the year, peaking in late summer into fall, year-to-year cycles are not so variable. Other sites, however, suggest a connection to the mast crop--we live surrounded by oak brush, and the number of acorns produced last year was at least average.

Maybe the number of foxes we are seeing around the house is connected to the mice, since they are a major predator. But it could also be because the foxes (at least the red foxes) have gotten used to scavenging sunflower seeds under the bird feeders.

It's a mouse-tery to me.

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