Periparus ater

Coal Tits are slightly smaller than Blue Tits, with olive-grey upperparts and buff underparts. Although they are reminiscent of both Willow and Marsh Tit, they have a characteristic head pattern, with a black bib, white cheeks and a black cap that extends down to the base of the neck at the sides. In the middle of this black cap, running from just below the top of the head back down to the neck, is a rectangular white patch, so this is one species where a back view can help identification.