American Goldfinch, Spinus Tristis

Day 208: The Goldfinches (Spinus tristis) are almost in full "bloom" now, having exchanged their drab winter colouration for summer's yellow plumage. They're still a bit pale, but even the females have taken on the greenish cast which makes them easy to pick out in a crowd of LGBs ("little grey birds"). In flight, there's no mistaking a Goldfinch. They fly like they're hanging bunting or a Christmas swag, in swooping dips followed by a peak which pins the top of the pattern: swoop, pin, swoop, pin, swoop, at last coming to rest on a branch or wire. As a human who has hiked trails like that, I can assure you that it has nothing to do with energy conservation, this going downhill just to climb back up again. So why has this flight pattern been selected for in their genes? Some bird species exhibit the same trait, but others are straight-line fliers, never losing altitude until it's time to land. There must be some advantage yet to be proposed by science for the swag-like flight of these golden ornaments of the sky.