small Japanese field mouse
Refers specifically to Apodemus argenteus, a small native rodent. In everyday contexts, it may be used loosely for any small field mouse.
The small Japanese field mouse is nocturnal and eats nuts.
I saw a small Japanese field mouse at the mountain hut.
Katakana spelling is common for this animal name; usually written in kana.
Kanji form is rare; the word is usually written in kana.
Compound of 姫 (hime, 'princess; small and delicate') and 鼠 (nezumi, 'mouse'). The name likely refers to its small size and graceful appearance.