Just a couple of degrees extra and life bursts out: baby rabbits on lawn for first time this year - bumble bees buzzing - ladybirds everywhere - tits nesting in hole in wall - blackthorn blossom in hedges... I rolled back the roof of my deux-chevaux to drink in the spring air.
Best of all was cycling to Oxford without any extra layers of clothing, whistling as I went. I wonder why there are not more whistling cyclists. It is the one form of mouth-music that you can make breathing in as well as out. And it helps pedestrians to hear you coming.
I wonder when early humans learnt to whistle. It seems to be something you need to be taught, but the first whistler must have foud it out for himself - or herself. A few days ago I was standing by a tree trunk with a hole in it, and the wind must have been at just the right angle and speed, and it began to whistle. Perhaps that's how it was discovered. Are there any other whistling mammals?