The only important location that can be reached by public is Kohoku Wild Bird Center. From Kyoto take JR Tokaido line to Maibara and change to the Hokuriku line getting off at Kawake station. There is a mini bus that runs to the wild bird center on the lake or the 6km walk across the fields can be productive, there can be Dusky Thrushes, lapwings, and Daurian Jackdaws on the fields and there are frequently Long-billed Plover on the river at Kawake near the station.
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My personal preference is to start with woodland birds north of the lake at dawn, snow depth affects access, then work down the east side. There are plenty of good locations in the north west too but fewer good birding opportunities heading south on that side of the lake.
Woodland species aren't much different to those found around Kyoto except White-backed Woodpecker is fairly common and Nuthatch and Treecreeper are possible. Japanese Woodpecker is more common up here and Elegant Bunting, very uncommon around Kyoto, is also to be expected. However woodland birding might be better thought of as an optional extra.
There are ducks everywhere on the lake though some are easier to see in certain areas, for example Goosander and redhead Smew are more common at the northern end while drake Smew gather further south. Baikal Teal are mainly at Kohoku-cho. Other rare ducks there have been include Green-winged Teal, Red Crested Pochard (annual), Baer's Pochard, Ring-necked Duck, Lesser Scaup, Ferruginous Duck, and birds like these could turn up anywhere.
This isn't actually the regular Steller's, others occasionally turn up and winter around the lake.
Many visiting birders I take there are keen to see Steller's Sea Eagle and the regular bird is easy to find at Kohoku-cho in the north east, though who knows how old that bird is or how much longer it will continue to winter there. This is also the best place to see Baikal Teal, Eastern Water Rail, a variety of ducks, birds of prey and birds of open country such as Daurian Jackdaw with any Rook flocks you come across.
If you stop at every likely spot heading south from there, you won't reach the southern end in daylight but it's risky recommending other sites because where birds might be is unpredictable and it may be better just to trust to your instincts. However the area just north of Omihachiman is often productive, Lake Sainoko is a roost site for Hen Harrier and Eastern Marsh Harrier and these can often be seen cruising along the edge of route 526. The fields stretching north from Sainoko to Lake Biwa can be interesting, Merlin, Daurian Jackdaw, Buff-bellied Pipit are all possible, there was a wintering Hooded Crane a few winters ago. The two rivers, especially the Notogawa are good for ducks and even waders. Long-billed Plover is frequently around the second road bridge from the lake on the Notogawa. Also the coast road around the wooded hills often has large concentrations of ducks and Black-necked Grebes, the commoner woodland birds are also well represented.
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