Biodynamics

The swifts have been out, and have got me thinking. How much energy does a swift get from eating one gnat? Presumably enough to cover flying and general maintenance until it catches another. The liveliness of their flying makes that equation hard to visualise, unless there are some special high-energy gnats out there. Since swifts live on the wing they must need a steady stream of such edibles, except for those times when a gnat-storm means they can bank some calories.

Amazing what you think about when cruising gently up the Middlewich branch of the Shroppie! It wasn't just the efficiency of swifts – I was also reflecting on the efficiency of Erin Mae's engine. We were doing as good a distance per rev as I've ever known. I'd throttled right back because we weren't in a hurry, but the Garmin told me we were still beetling along (it's all relative, of course – I mean 2.5 mph). Perhaps the engine is more efficient at lower revs – I don't imagine the biodiesel suddenly got more dynamic.

I'm gad I'm not on gnats or diesel. We had a nice chicken curry tonight.