Smallest woodpecker in Japan

Kogera is the smallest woodpecker in Japan as small as sparrow. "Ko" mean small and "gera" mean woodpecker in Japanese. They live in forests, but recently they can be seen even in urban areas.
Strain your ears, you can hear not only tweets but also drumming (pecking) sounds. They peck holes in trees to catch insects and worms under the bark and to make them nest. Once you find them, you can observe them all season and long term because they stay at same place for a long time with their partner.