Many thanks indeed; your trouble & conclusions greatly appreciated. The two duetting girls do indeed put in some pauses; but not so much before that clinching final monosyllable - which they do however elongate: thus it gets emphasis, but of not quite the same sort.

It does indeed seem to be a German song in origin probably. Which leaves the question as to how did it get here, surfacing in my nephew's London school in the 1950s, as part of pupil culture, rather than as part of taught curriculum so far as I can see, and with the final gastro-dietetic moral as an addition, which seems to belong purely to the English version & make it more interesting in some ways — tho I can see the force of the idea of the defiance to Nazi persecution, in the bird's death but subsequent regeneration, suggested above?

The Opies, whose Lore & Language Of Schoolchildren appeared when my nephew was 10 [ie about when I learned it] in 1959, don't appear to have come across it despite the comprehensiveness of their methods & discoveries; &, tho I met them some years later, interviewing them for Folk Review in 1970s, I don't think it occured to me at the time to pass it on to them.

An interesting comparison - ah - nichtsdestoweniger, nicht-war?.