why they say a perpetum mobil its imposible what about the drinking bird?

[major_setback]

How much energy could you get from 1 bird?
I think we will need a few hundred to power a small working-class household (1 computer and 1 lightbulb during summer), or a dozen third world houses (same but no computer).
Large scale production is essential if it is to work, and we will see large dippy birds all over the countryside, which will be fine in most of Europe, but the British will complain that it is making the place look a bit of a mess. There will be protests involving setting leading members of parliament on fire and 'women of a certain age' chaining themselves to Noel Edmunds.
So I can't see it happening. Not in Britain anyway.