[medved]

Penguins and ostriches DEVOLVED from flying birds; you'd expect them to have flight feathers or at least it wouldn't surprise you. But a flight feather is a major engineering advance which could not plausibly evolve from hair or insulation feathers. It has complex structure, interlocking barbules etc., and a complex system for allowing it to be turned so that the flight feathers open like a venetian blind on upstrokes and then close again on downstrokes, and without all of that, the whole thing is useless.

[jennyp]

But a flight feather is a major engineering advance which could not plausibly evolve from hair or insulation feathers. It has complex structure, interlocking barbules etc., and a complex system for allowing it to be turned so that the flight feathers open like a venetian blind on upstrokes and then close again on downstrokes, and without all of that, the whole thing is useless.

That's all very nice. But the articles say these latest feathers are "mature". I assume this means they have a central shaft with filaments coming off it at intervals. Who should we believe, then? Your excluded-middle theories for why it should be impossible, or our lyin' eyes?