Sunday, September 20, 2009
Why do birds look different up and down wind?
Why do birds look different up and down wind?
birds flying into the wind always look somewhat different to those flying downwind.
Yet if the wind were constant, the bird would find it difficult to tell that it is in a wind at all, let alone which direction it is in. In perfect conditions there should be no difference.
So the observations either relate to turbulence of some sort, or the bird having some idea of absolute speed relative to the land.
One can imagine the later, in that if the bird wanted to optimise his use of energy, then he will probably want to fly harder in a wind against himself, and slower in a following wind. Indeed in a strong following wind he probably wants to keep near to stalling speed, and that probably really does change how he will look.
I will have to have a good look next time
cheers
martinW
birds flying into the wind always look somewhat different to those flying downwind.
Yet if the wind were constant, the bird would find it difficult to tell that it is in a wind at all, let alone which direction it is in. In perfect conditions there should be no difference.
So the observations either relate to turbulence of some sort, or the bird having some idea of absolute speed relative to the land.
One can imagine the later, in that if the bird wanted to optimise his use of energy, then he will probably want to fly harder in a wind against himself, and slower in a following wind. Indeed in a strong following wind he probably wants to keep near to stalling speed, and that probably really does change how he will look.
I will have to have a good look next time
cheers
martinW
