I am reading David Nutt’s book Drugs – Without the Hot Air, which is excellent, although as I will get to later, my timing is not great. Incidentally, as he admits in the book, he is best known as the scientific advisor that the then Home Secretary Alan Johnson sacked a few years ago. He says a number of things in the book, but I can illustrate a key point he is making as follows. Consider two drugs: A and B. Large doses of A can kill you on the spot, it is responsible for damage to society on a huge scale, tens of thousands of deaths every year, and can be addictive. Drug B does not, even in very large doses, kill you directly, although it is harmful. It is also not addictive. If you tell you one of these in legal and the other illegal, can you guess which one is illegal?
I have just learnt that the European Starling can take its drink. Alcohol is metabolised, in starlings and in us, by an enzyme called Alcohol Dehydrogenase. By weight starlings have approximately 14 times as much Alcohol Dehydrogenase activity as we do. The data are in a paper by Prinzinger and Hakimi. I will now look at starlings with new respect.
You may be asking yourself, why do European Starlings have this impressive ability to take their drink? Fruit is a major part of the diet of starlings. Fallen fruit tends to ferment of course, which produces alcohol. So it may be that starlings have evolved a high tolerance to booze to allow them to eat lots of fallen fruit without then being reduced to zig-zagging across the sky in a rather drunken way.