Responses

On the contrary, it's very symbolic. The cuckoo is a bird that steals other birds nests, and lays an egg that will take the place of the other original eggs that were in the nest. So you can see that Seno could be the "cuckoo" of this story, wanting to take Hakushima place in Natsuka's "nest" (aka heart).
And the ending was beautiful, but when the cuckoo chirped at the end I DIED LOL WHYD THEY HAVE TO PUT THAT CUCKOO IN THERE AND WHO CARES IF IT CHIRPS LOL HAHAHAHA