Kiso Valley, Japan

I spent three nights spotlighting around Kiso Valley in Honshu. It was raining, and mammal activity was very low (I didn’t see any carnivores or deer, which is unusual for Japan), but I found some good sites:

1. Akasawa Natural Recreation Forest: the forest seemed strangely devoid of mammals, except for one hare near the visitor center, but the river is a textbook example of Japanese water shrew habitat. Blue trail (1.5 km) provides access to a few bridges that make perfect observation posts; I spent six hours there and saw one water shrew from the bridge at 35.729168N 137.625744E. You need a thermal imager because the shrews seem totally intolerant of light. The river also looks good for giant salamanders, but I didn’t see any.

2. Mount Ontake: there are two roads from the SE side to the summit area; one goes up to 1800 m where you can take a cable car to 2200 m; I didn’t try it because the cable car was closed due to weather. The other road ends at 2200 m. The last few km zigzag up a grassy ski slope where hares were abundant despite heavy rain and strong wind; in better weather there should also be voles there. Near the summit parking lot there’s a network of boardwalks through dwarf conifers and small bogs; I saw more hares there and found an Azumi shrew hiding under a boardwalk at 35.873620N 137.502475E. There were red-backed vole burrows in that area. In good weather you can reportedly hike to alpine meadows where mountain mole, lesser Japanese shrew-mole, and serow are said to be common (ptarmigans as well). When I was driving back down in the morning, the rain stopped for half an hour and I saw a family of wild boars and a herd of macaques; in better weather it’s probably a good idea to spend a night just driving up and down that road as there are many interesting habitats and no nighttime traffic. The road is also excellent for herps.

3. Kakizore Gorge. The trail to and beyond the waterfall passes through rare low-elevation habitat of Shinto shrew. Serows can sometimes be seen on winter weekdays. I was there during the day and didn’t see any mammals.

4. Torii Pass (1210 m) is a popular hike, but you can also get to the top by car (the road is marginally passable for a sedan). 200 m south of the pass the main trail crosses a patch of oldgrowth horse chestnut forest (35.950872N 137.795254E), extremely rare in Japan. This area and two stream crossings along the access road from the south were the only places with lots of mammals: in one night of walking around I saw a bear, a wild boar, a dozen greater and a few lesser Japanese mice, a few Anderson’s red-backed voles, two Japanese white-toothed shrews (one of them caught and killed a vole as I watched it all through the imager), and two Oriental black rats (I wonder if such forests were their preferred habitat before they colonized ricefields and other human-modified habitats; note that contrary to most Western literature, this species is native to Japan as there are Pleistocene fossils from Honshu). Endo’s pipistrelles and dormice live in chestnut hollows, but the latter are pretty much impossible to see well. Watch for tiger keelbacks.


  • Conuropsis

    Nice stuff. I’ll have to try and get there for the mammals and birds someday. Question about viewing with the scopes, are you locating the animals with the scope and then shining a light on the animal to id it or just using the scope? When I tried Jon’s I could not see any detail just a whitish animal image. How are you able to id the critters, especially small rodents, with just the scope if that’s what you do? Just wondering:-) Thanks.


    • Vladimir Dinets

      Yes, IDing small mammals to species with just the imager is seldom possible. After a lot of practice I can usually tell shrews from rodents and sometimes mice from voles, but if I get to a place like South America or Sulawesi I’ll need a lot of time again just to get to a similar level. You have to get as close as you can and turn the light on; a lot of times it doesn’t work (the animal disappears too early or too quickly) and that’s very frustrating. I’m considering using a “standard” infrared camera in addition to the imager because it gives you a better idea of what the animal looks like.

      • Conuropsis

        Thanks Vladimir. I’m amazed how well you and Jon do with the small mammals in general. Unless I had a field guide I’d be lost with most small rodents and such in foreign countries.

        • Vladimir Dinets

          Well, I live in Japan, and I do have a book, although it’s not really a field guide. Besides, small mammal diversity here is not particularly high.

  • Jon Hall

    Andrew I am indeed lost with many small mammals. a lot of the time, First, I almost never see as many as Vladimir does. Second, when I do see one I generally get a short look at something which generally is along the lines of “Ohh look its a … shit its gone”. Even when I have great views, pictures or even animals in the hand with detailed measurements it can be extremely hard to get down to species level when differences in measurement and colouration can be so subtle. So I nearly always try to check my pictures with an expert and a lot of what I see (which isn’t a lot) isn’t IDable,

  • Vladimir Dinets

    I’m not sure I see more small mammals per hour than Jon, but I put in a lot of nighttime hours. Also, since getting a thermal imager I’ve been doing a lot more sitting and waiting at good spots.
    As for identification, every time I’m about to travel to a new country, I make a checklist with ID tips for every species (except obvious ones). That way you know which details to pay attention to.
    I wish I was as good as Jon at organizing trips in general. His skills at finding useful local contacts are amazing.

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