mramshaw

What tells you there're no controllers? Large flocks work somewhat like a tree, they're devided into clusters and each cluster acts as a leaf to the next larger one. Given the reaction time each cluster aligns on one bird and follows it slightly delayed which gives these impressive movements.

My take is this: the birds' "processing units" are fast enough to react to spontaneous direction changes in their vicinity. You could say they have a much higher "clock rate" than humans, so they can also react faster. I often notice this with smaller birds like titmice, they appear somewhat hectic and nervous. But that's just the way they work... they have a very fast metabolism, they never seem to sit still for more than one second, it's like a constant motion.

Thanks very much guys.

@nachbar, thanks for spurring me into GIMPing. They can form into clusters (a flock often divides mid-stream) but I don't think your leaf analogy is quite right. They do follow leaders, but the leaders rotate, there's a big advantage to flying in flocks as they can utilize vortex eddies to save energy, but it's simply too tiring for one bird always to be the leader, so leadership rotates (like in a cycling peloton or how cross-country skiiers take turns breaking snowpack or crust).

@Quantumleaper, you're absolutely right, Hummingbirds are incredible, they have absolutely no fear of humans as their metabolisms are approximately 10 times as fast as hours (600 bpm compared to approx. 60 bpm). I think we must look like slow-moving glaciers to them. Perhaps when they hibernate (estivate?) overnight we look like we're moving real-time to them.

Anna, thank you very much [for the fav also], it was my pleasure and I am glad you enjoy them too.

oh, very pretty

@brinjal, Thanks for the fav.

WD!

Thanks for the favourite @15, you have moved me into a very select company.

Thanks Sonja, you really cannot beat being in the right place at the right time.