Here's my translation of the song that MtheGM found on YouTube - it's lacking the last verse as posted above by Joe, but otherwise it's the standard children's song. A German friend of mine who sings this song says it had some special significance among the German resistance during WW2 (ie, others would replace those who were eliminated by the Nazis).

Upon a tree a cuckoo
Simsaladim Bamba Saladu Saladim,
Upon a tree a cuckoo sat

A young hunting- came there
Simsaladim Bamba Saladu Saladim,
there came a young hunting-man

He shot the poor cuckoo
Simsaladim Bamba Saladu Saladim,
He shot the poor cuckoo dead

And after a year
Simsaladim Bamba Saladu Saladim,
And after a year had passed

The cuckoo was again
Simsaladim Bamba Saladu Saladim,
The cuckoo was again there

This made the people happy
Simsaladim Bamba Saladu Saladim,
This made the people very happy