Naumann's Thrush is seen from autumn to spring in Koshimizu, eastern Hokkaido. It forms flocks in woodland and open areas, feeding on insects, earthworms, and rowan berries on the ground.
The common form described for Koshimizu has blackish-brown upperparts and a pale cream eyebrow. Its white underside is marked with black spots from the breast to the flanks, and the pattern varies among individuals.
It is seen in Koshimizu from autumn to spring and searches the ground in flocks for insects and earthworms. It also eats rowan berries; flocks have been recorded feeding on lawns and pastures in spring.
An extinction-risk assessment has not been added yet.