This is the 310th most frequent Norwegian word.
liten
Small.
Here, 'liten' is used as an attributive adjective modifying the noun 'bok' (book) to describe its size.
Jeg har en liten bok.
I have a small book.
In this sentence, 'liten' describes the size of the bird ('fugl'), functioning attributively before the noun.
En liten fugl satt på grenen.
A small bird sat on the branch.
In this usage, 'liten' is a predicative adjective describing the subject 'han' (he), indicating a diminutive feeling or state in a figurative sense.