In Japan it occurs in mountain woodland from Kyushu northward. A black cap on the head is conspicuous.
It has a black cap and whitish cheeks. The back is brownish and the underparts pale.
Near Oulu in northern Finland, Willow Tits hid food most often in September. Lange and colleagues observed wild birds on 79 days between August 2005 and May 2006, then examined adult brains collected in different seasons from 2006 to 2007. In Willow Tits, the hippocampal formation, a brain region involved in remembering cache locations, was largest in September; the number of neurons there also peaked that month. The timing of the brain changes matched the local peak in food-storing behavior, leading the authors to suggest that forming many new memories of cache sites may contribute to the change.
Great Tits, compared as a non-hoarding relative, also showed seasonal brain changes, but in a different pattern. The authors suggested that seasonal shifts in flocking and home-range use may help explain the Great Tit pattern. The study linked field behavior and brain measurements in birds around Oulu, Finland.
IUCN Red List (BirdLife International) · Least Concern (LC) · Global
BirdLife International’s 2019 global IUCN Red List assessment listed the Willow Tit as Least Concern (LC), with a decreasing population trend.