Liedsatz und Fuge "Der Kuckuck weckt schon früh den Tag"

A few days ago I discovered this song from 1997 and have now built a fugue to it. The melody is by Klaus Gerlach, who has composed some songs and about whom I have unfortunately found nothing further.

While writing the fugue, I noticed that the melody starts the same way as the Marseillaise and simply continued it in the last bars in the middle voice.

At first I experimented with playing the song on the Giubiasco and the fugue on the Melcer Chamber Music Hall. Technically this is no problem, but the song movement does not sound on the Giubiasco organ - never mind, maybe another time.
So we'll just listen to the Melcer Chamber Music Hall organ.