Shrew plague

Over the last few months, I’ve heard a few people complaining that they’ve never seen a shrew in the wild. I couldn’t really help them, because I don’t know any places where seeing a shrew during a short visit would be guaranteed.

Well, right now there seems to be a shrew population explosion on the E side of Hatcher Pass, Alaska. I just spent 6 hours there (starting at midnight) and saw 12 shrews, including a pair fighting and chasing each other. A few of them could be observed running around for 10-20 min. The best place is a steep sandy roadside slope about 100 m past the sign “Entering Summit Lake State Recreation Area” (driving E to W).

This was only a second time that I’ve observed such a multi-species shrew “plague”. The first one was on Nyiragongo Volcano in 1995.

The road to the pass is officially closed, but the gate is often open, and in any case it’s only a 1 mile walk from the gate. The opening date is July 4; I don’t know if increased traffic will have any effect.

Look also for collared pikas on talus patches there, and for brown lemmings in boggy streamside meadows.


UPD: looking at the photos, there are clearly three species present. I think the larger ones with light flanks were tundra shrews, the smaller light-colored ones were montane shrews (the most common), and the single dark at the beginning of the pass road was a masked shrew.

  1. mattinidaho 7 years ago

    Hi Vladimir, very interesting. When I was a kid in Pennsylvania, I could see them by staking out vole colonies and other little clearings. A lot of that habitat is gone now, at least where I used to look — it’s now houses and lawns. The shrews are still around but are harder to see.

    I have had no luck spotting the shrews along the Boise River near my home. I believe they are vagrant shrews. I have seen some dead ones on the Greenbelt path but never living ones. I should double down on efforts, but in any case they are not a very visible mammal.

    I have written a couple of blogs about research on shrews & fish in Alaska. There must be a fairly significant number some years for rainbow trout and grayling to specifically target the shrews.

    Here are the blogs:
    A rainbow trout with 19 shrews in its stomach in Togiak NWR:

    How often do trout and grayling eat shrews, based on an Alaskan stream study:

    • Author
      vdinets 7 years ago

      Yes, I remember those blogposts. At the time you posted them I was completely puzzled, but now I think I understand how it’s possible.

  2. steve linsley 7 years ago

    OK, Vladimir,
    I’ll stop my complaining about never seeing any shrews.

    • Author
      vdinets 7 years ago

      It wasn’t just you 🙂 I’ve heard it from a lot of people. I also often go for months without seeing one.

  3. […] set 80 sherman traps around the pass that night. But despite Vladimir Dinets’s reports of a “shrew plague” a month earlier I caught […]

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