A classical poetic term for deer, likening them to birds among autumn leaves. Used in waka and traditional literature; not used in everyday speech.
See also: 鹿
'Momijidori' is an elegant word found in waka poetry that refers to deer as an autumn feature.
Compound of 紅葉 (autumn leaves) and 鳥 (bird). The exact origin is uncertain, but it is a classical metaphor comparing deer moving among autumn foliage to birds.