5 books in series

囀る鳥は羽ばたかない [Saezuru Tori wa Habatakanai]

囀る鳥は羽ばたかない [Saezuru Tori wa Habatakanai] is a 5-book series with 5 released primary works first released in 2013 with contributions by Kou Yoneda.

Twittering Birds Never Fly, Volume 2
TWITTERING BIRDS NEVER FLY VOL 04
Twittering Birds Never Fly vol 5
Twittering Birds Never Fly, Vol. 6
Twittering Birds Never Fly vol 7