the online database of Japanese folkore

Aosagibi

青鷺火
あおさぎび

Translation: blue heron fire
Alternate names: goi no hikari (“night heron light”)
Habitat: rivers, wetlands; wherever herons and other waterbirds can be found

Appearance: When they reach an advanced age, many types of birds transform into magical yōkai with eerie powers. Aosagibi is the name for a bizarre phenomenon caused by transformed herons—particularly the black-crowned night heron. Found all along the islands and coasts, this heron prefers remote areas with heavy reeds and thick woods. Though aosagibi is most commonly attributed to this particular bird, other herons and wild birds such as ducks and pheasants are able to develop this manifestation. Aosagibi is most commonly seen at night, either in the trees where the herons roost, by the rivers where they hunt, or in the twilight sky as birds fly overhead.

Behavior: Long-lived herons develop shining scales on their breasts, which fuse together from their feathers. With each breath, they blow a yellow iridescent powder from their beaks that scatters into the wind. During the autumn nights, their bodies radiate a bluish-white glow. Their powdery breath ignites into bright blue fireballs, which they blow across the water or high in the trees. These fireballs possess no heat and do not ignite what they touch, but eventually evaporate in the wind.

Interactions: Like most wild birds, night herons are shy and flee from humans. Even after transforming into yōkai, they retain their shyness. While the sight of a colony of wild birds breathing blue flames and making strange calls on a cool autumn night can be rather disconcerting, aosagibi does not post any threat. However, because their fireball breath appears similar to other phenomena, caution should be taken to avoid confusing aosagibi with onibi or other supernatural lights.

Alphabetical list of yōkai