Another early evening walk around the lanes. I took a nice photo of a meadow pipit perched on a shrubby twig. When I posted the photo on Facebook, an old friend who knows far more about birds than I could ever dream expressed envy at our having tree pipits in the area. This, of course, set me off on an hour’s research into how to distinguish tree pipits from meadow pipits. It’s all down to the stripes on the flanks and the length of the back claws, apparently.
The extreme difficulty in telling certain closely related species apart rather drums home the point Darwin repeatedly made that determining whether two organisms are from different but closely related species, or mere varieties of the same species, lends considerable support to his belief that varieties can sometimes eventually become species. Species are effectively varieties writ large.
Anyway, on more careful reflection, my friend and I eventually agreed my meadow pipit was indeed a plain old meadow pipit. Which is fine by me.