Hokkaido Bird Looks Like Flying Cotton Ball

While they generally thrive well in winters, harsher conditions will lead them to huddle or flock together to maintain warmth.
They are already small in size, but even smaller birds are prone to losing more body heat compared to the larger ones, so they are actually at risk of dying when a partner is not found. Therefore, they flock together in specific groups: brothers, sisters, uncles, and aunts.