Just spent a few days on Hokkaido. Small mammal and fox numbers are very high; hares are totally missing.
1. Sendai-Tomakomai ferry worked out great: a mixed group of Pacific white-sided and right-whale dolphins, a pod of Baird’s beaked whales, and pilot whales.
2. Rishiri-Rebun NP. Saw a distant group of killer whales from the ferry to the island and harbor porpoises on the way back. There was a least weasel at Panke Marsh picnic site (45.033367N 141.732555E). I had big hopes for the island but saw nothing worth reporting except an Ussuri whiskered myotis squeezed in a very narrow slit in a rotten snag where I forgot to get GPS coordinates.
3. Lake Oketo: what a great site! I parked at 43.613853N 143.378868 and immediately saw a Hokkaido red-backed vole across the road. Walking NW, saw 4 Siberian flying squirrels (listen for soft, short, treecreeper-like whistles). Walking SE, saw northern bats feeding around street lights; also found a Korean mouse eating ants at an anthill, but while I was watching it through my thermal imager, a boreal owl scooped it up and disappeared. Unfortunately, I was only there at night.
4. Lake Nukabira-Lake Shikaribetsu Rd. At night there was a mass flight of small geometrids (multiple spp.); the road was covered with them, and all kinds of animals were feeding on them: an Oriental scops-owl, 20+ Laxmann’s shrews (one caught by hand to confirm the ID), 5+ long-clawed shrews, 1 slender shrew, many Ikonnikov’s myotis, 30+ foxes, 1 raccoon dog, 1 sable, 3 lesser Japanese mice, and the rarest of all, 1 non-feral Norway rat. Also a few sika deer there; one was so tame that it stuck its head inside the car and licked my hand. At Horoshika-toge Pass (43.337944N, 143.161194E) there is an excellent side road, very level; it is great for birding and there are pikas at the edge of a landslide at the end of the good part of the trail. Lots of old bear tracks.
5. Akan-Matsu NP: Rd 241 just outside the park has lots of abandoned houses and I checked some for bats, but found only a few Japanese long-eared bats.
6. Ozona: the large bats flying around the village at night are particolored bats, extremely rare in Japan. They used to roost in the old gymnasium, but I found only long-eared bats there.
7. Shiretoko NP: Furepe Falls trail had lots of rather tame (but still too quick to photograph) northern and grey red-backed voles in the forested part, and fraternal myotis night-roosting in trees around the visitor center. A fin whale was visible far offshore. According to the logbook at the visitor center, a brown bear was seen daily around 8 am, but I was in the park only in the afternoon, so I had to spend a lot of time looking for bears. Eventually found one at night along Iwobetsu Rd. (44.102393N 145.053518E), but it was eating something (probably a deer fawn) in dense bushes, so I decided that taking close-up flash photos would be impolite. At Shiretoko Pass there was a surprisingly shy chipmunk. I also walked a bit along the eastern coast of the peninsula; saw fins of Dall’s porpoises far out. No salmon in rivers yet.
8. Kushiro Marsh: I followed Yann Muzika’s advice and spent a few hours at Lake Tokkobu (43.068957N 144.466051E). The area was by far the birdiest of the trip, and I found colony of myotis bats (I think Ikonnikov’s but will have to check) in a woodpecker hole in a snag on the left side of the trail soon after the end of the boardwalks. Also found a least shrew at the edge of the pond. On the main boardwalk on the W side of the marsh there was a very friendly mink. A pavilion in Murata Park (park at 43.109928, 144.489408 and walk on for a few minutes) used to have a huge roost of Asian particolored bats, but now there are only dozens of Japanese long-eared. Tsuhsui Bridge (43.108971N 144.229005E) had night-roosting Far Eastern myotis.
9. Tokachi Station of National Livestock Breeding Center has a famous old wooden building (43.064322N 143.159217E) that used to have 8 species of bats. But now only long-eared bats are left. I was really surprised to see so many of them everywhere I checked: they are supposed to be very rare, and certainly are on Honshu. Nearby, Eastern water myotis roosted under the bridge at 43.048706N 143.137257E.