( By the way, this all happened a week or so ago ) ( I've been wondering if I should put it on here. ) (It's not funny, nor are there any daft poems in it.) You're gazing at the garden .... and you decide to note down the number of different bird species you see each minute. Well, I did that very thing yesterday for 84 minutes .... Crumbs ... you're thinking. But I did it over 6 sessions of 14 minutes each, whenever I had a bit of spare time. That way I didn't get bored. Or tired. Nor did I fall asleep. There were 29 minutes when I saw no birds at all and 33 minutes when I saw only 1 species and 13 minutes when I saw 2 species and 7 minutes when I saw a massive 3 species and 2 minutes when I saw an incredible 4 species and also 2 minutes when I saw ... crumbs ... 5 species Let's make a nifty table of it shall we .. Number of species seen 0 1 2 3 4 5 How many times 29 33 13 7 2 2 = 86 minutes Sp. sightings . 0 33 26 21 8 10 = 98 "species-sightings" Mean number of species /minute = 98/86 = 1.14 If we plot this out, it doesn't look like a Normal Curve at all. It's far too lop-sided for a start. ..... and then, I did a bit of mathematical magic ..... which I used to "predict" what the results "should" look like .... here is the prediction, plotted in red on the same graph........ I hope you are all impressed. Pretty close to the "real" results. Coo ! The prediction for "2" is a bit out, but overall ...pretty good. The "real" and "predicted" plots keep pretty close together. It's a cracking example of the power of the Poisson Distribution. And all you need to work it out is ..... something we've already got ... The Mean number of species /minute = 98/86 = 1.14 I worked out those " predictions" from that ! It hardly seems possible .... but there it is. How exciting is that ? I'm happy to show you how it's done ..... But I have an odd feeling that my readers might not be interested . In fact, they might run into the hills and never return. And I don't want that. There's very few of you as it is. Hey ..you could look up how it's done yourselves. (But don't, whatever you do, look at the videos about it.) They are all specially designed to confuse and confound your entire being. But I can explain it properly. Then you can do it too. Tell you what ..... you can tell me if you "want" it in the comment thingy. And ... if I get a "yes" majority I'll do it. And if I get a "no" majority I'll file it away under " No, no, and thrice no !" Oh ..I did do some "proper" birding as well. In the pm I spotted a fly-by Med Gull .... v. nice. And at breakfast time there was a Juvenile Jay on the picnic table. Isn't that the name of one of those " rappers" ?? And I saw 16 swifts ... after seeing none at all for 5 days. And there was a grasshopper on our front wall in the sunshine. And.... at night, there was a male Tawny Owl hooting away... ..and even better, TWO Little Owls wow-ing like mad. "Littles" have become v. scarce in my little 3K patch ... and beyond. So I was unduly chuffed. And duly chuffed too. How can that be ? Instead of the music, we're going to have a video about " The Best Equation" and despite what you might think, it's funny, entertaining and true. And what's more, one of those people has been to my house. And not just to read the gas meter. Oh, go on then, we'll have some music as well ... So ..get voting or lose out on a lifetime opportunity .
Maybe that's a slight exaggeration. That prediction was pretty neat though .... you've got to admit it . I delayed putting this on here in case all of my readers ran off into the long grass ! And if they do, I hope they've read my warnings about Lyme disease . 583-the-hazards-of-birding-lyme-disease.html
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AuthorThat's the author up there ... I was young and sprightly then. Archives
October 2022
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