As for bird intelligence - I will try and match controversial comment with controversial comment. How do you measure 'intelligence'? An anthropologist recently suggested that when Neolithic Man developed the software to kill a large and formidable animal like a Woolly Mammoth, that could be termed as human progress as it provided him and his family with meat for several weeks. When he refined the software to bump off two mammoths at a time that was a further advance in progress. But when he devised the means to drive two hundred mammoths over a cliff he was a ruddy idiot unless at the same time he redesigned his hardware to cope with this new technology by learning the virtues of self restraint and switching from short term to long term planning. Fast forward to the 21st century and the need is even more pressing. So how far have we got along that road? Not very far I would suggest. Forget evolutionary theory. Most human beings merely pay lip service to it. What most of us believe is that "Evolution created man in its own image and gave him dominion over the bests of the earth". We have come to see ourselves as potential Lords of the Universe when, in reality, we can't even master our own nature! We also seem to believe (perhaps all too often encouraged in this by scientists in search of funding) that our software will always be able to come up with a technological 'fix' to save us from our every folly. Perhaps that is why we resent those scientists who state that we need to mend our ways. The science we believe in is the one that invents cures for horrible diseases or provides us with an endless succession of new toys to play with. Being told to mend our ways is the job of priests, not scientists, and no one listens to them anymore. We have come to expect a pill for every malady rather than lose weight, get more exercise and stop smoking! Which is probably why so many of us retreat into denial (or even treat the bearers of bad news as 'Quacks') when confronted with the findings of Climatologists and the like, however impeccable the science. Just how intelligent is that?!!!
With regards to the walnut cracking crows in Japan which I mentioned elsewhere, I presume they devised (if that's not too strong a word) their little ploy after watching nuts that had fallen into the road naturally being cracked open by passing cars. As for the African Grey Parrot you mention, with all due respect to your wife's cousin, I reckon that if I was a highly sociable bird like a parrot and was stuck in a cage on my own I would go do-ally long before my hundred or so years on this earth were up. I once rescued an escaped Budgie from the side of a road and took it to a woman who kept a large aviary of them. After a due period of quarantine - to make sure it was not carrying a disease - she invited me back to watch it being introduced to the other birds. As we approached the aviary and it could hear the Budgies inside it became very excited and when she place its cage outside it performed around fifteen gold medal somersaults on its perch, such was its joy! On the same theme, make sure that you are not crossing a field where cattle that have spent the winter in a barn are about to be released. Excited is not the word. They prance across the field like Springboks, chasing each other's tails and rolling ecstatically in the grass. Animals know what they like. They ain't daft!