Wikipedia:Reference desk/Archives/Science/2020 March 28

= March 28 =

Coronavirus spike


Why the spike in China on February 17th? Some sort of new test? And do we believe they had essentially no new cases in March? --Guy Macon (talk) 12:58, 28 March 2020 (UTC)
 * They changed their diagnostic criteria (here, here, or here). Fgf10 (talk) 13:33, 28 March 2020 (UTC)
 * Yes, that is the day that the Chinese suddenly caught up with a looser but more realistic assessment of who was almost certainly infected. I do not know whether they are deliberately lying about case count at this time, but they are under intense international scrutiny. Cullen328  Let's discuss it  04:07, 29 March 2020 (UTC)
 * AFAICT that is incorrect or misleading. As per the above sources and Template:2019–20 coronavirus pandemic data/Mainland China medical cases chart and maybe [//en.wikipedia.org/w/index.php?title=Template:2019%E2%80%9320_coronavirus_pandemic_data/Mainland_China_medical_cases_chart&oldid=942965050], the change was before 17 February. The above sources suggest 12 February, our article suggests 10 February. This may depend on what source of data (figures reported to WHO, Chinese figures released on their website etc). And maybe it took a while before they added all clinically diagnosed cases. There may also be 1 or 2 days lag depending on how the various parties report the data. But no source provide so far suggests 17 February was the date of such a change and 7 days lag seems way too long. 16 February was when the Chinese stopped providing separate figures for laboratory confirmed and clinically diagnosed cases. So it's possible that the 17 February jump comes because the WHO was discounting clinically diagnosed cases until they couldn't do so. But it seems misleading to suggest this was "more realistic assessment" when the Chinese authorities had been providing the numbers for days and the WHO chose to discount them. It's also possible it's simply a mistake, the WHO has made them before, generally corrected when someone pointed it out. Or it's also possible whoever made the graph made a mistake. While these was a jump, I'm not convinced it should have been that great even if the WHO has been ignoring clinically diagnosed cases until then. Nil Einne (talk) 08:18, 29 March 2020 (UTC)
 * It seems that WHO was excluding clinically diagnosed data, but on 16 Feb China stopped supplying it separately from lab confirmed so they had no choice but to count it all together. 89.172.8.37 (talk) 08:22, 29 March 2020 (UTC)
 * (EC) Actually looking more carefully I withdraw my last sentence. Nil Einne (talk) 08:24, 29 March 2020 (UTC)
 * I'll be glad to know how to create similar curves as shown just before the question. I intend to create one for data in my country. Thanks, בנצי (talk) 22:41, 31 March 2020 (UTC)

Blue Tits, milk bottle tops, gulls and worms.
Those of us in the UK, old enough to remember having our milk delivered in foil covered bottles, will no doubt also remember finding that the top had been smashed in and the cream guzzled by Blue Tits. Someone once told me, that from the first occurence of this being reported, the practice spread throughout the country in less than a week.


 * Firstly, is this true, and if not, how long did it take the entire native Blue Tit population to learn this skill?


 * Secondly, I have often seen gulls stamping the grass, presumably to attract worms, but this is not something I ever remember seeing in my childhood. So, when did gulls learn to do this (if indeed that is what they're doing), and how quickly was it passed around the country?

Thanks in advance--Ykraps (talk) 18:16, 28 March 2020 (UTC)


 * See THE OPENING OF MILK BOTTLES BY BIRDS by JAMES FISHER AND R. A. HINDE, which details the learning process (a bit longer than you were told, but remarkable nonetheless). For non-British readers, see blue tit, whose naming is an invaluable resource for schoolboy comedians. Alansplodge (talk) 18:41, 28 March 2020 (UTC)
 * And for anyone too young to be familiar with the practice of milk being delivered, see milkman. --69.159.8.46 (talk) 18:51, 28 March 2020 (UTC)
 * Comment: Amazingly enough it turns out is not just age-related. After a gap of many many years we suddenly started to get doorstep milk again. It's great! And what with er er the modern age and everything, he takes online payments and what have you. Bl**dy marvellous. The former dairy depot is now a Wetherspoons so I don't know where he's coming from. Oh, and the blue tits have not yet sussed it out ... give them time, I guess. 82.39.96.55 (talk) 00:30, 30 March 2020 (UTC)

Hear, hear. We have used one for 12 years. In recent days (Covid19) so many people have been signing up it has overwhelmed the delivery companies. Richard Avery (talk) 07:35, 31 March 2020 (UTC)
 * Somewhat surprisingly, there are quite a few sources for the blue tit/bottle cap story. For example:
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)
 * 107.15.157.44 (talk) 18:52, 28 March 2020 (UTC)


 * On your second question, this article has some theories by Nobel Prize winner Nikolaas Tinbergen, but nothing to suggest that it is a recent innovation. Alansplodge (talk) 18:55, 28 March 2020 (UTC)
 * Evidently it is commonly known as "seagull rain dance" (plenty of search results for that. -- It is believed that worms are fooled into thinking that it is raining.) 107.15.157.44 (talk) 19:16, 28 March 2020 (UTC)
 * And even people do it - see worm charming. Mikenorton (talk) 20:01, 28 March 2020 (UTC)

Related: Japanese macaque and Social learning in animals. Especially interesting is Social learning in animals. --Guy Macon (talk) 19:54, 28 March 2020 (UTC)


 * James Fisher (naturalist), BTW Andy Dingley (talk) 22:00, 28 March 2020 (UTC)

I was always dubious about the within-a-week story because there didn't seem to be a large enough population of blue tits. Nevertheless, it's massively disappointing to find out it isn't true. Curse you internet! Still, we've still got the gulls to argue about in the pub, when it eventually opens! Some interesting stuff found so thanks one and all for digging it out. I will make sure I get the story about the divvy robins in, when next the subject comes up! , I think the schoolboys were more interested in Great Tits. , as a young angler, I too used the worm charming method, until I discovered it was far more efficient to chuck a bucket of soapy water on the lawn.--Ykraps (talk) 07:10, 29 March 2020 (UTC)