[Adam Pinsky]

Adam Pinsky  asked the Naked Scientists:

Hello Dr. Chris and others

My name is Adam and I am a loyal listener from Canada and I love the
podcast. Keeps me entertained on my Wednesday's at work!

My question is how to birds maintain formation in those huge flocks of
thousands. And do they ever crash into one another?

Keep making science fun.

Cheers,

Adam

What do you think?

[RD]

Flocking amazing...

Flocking simulator...
http://www.lalena.com/AI/Flock/Flock.aspx

[LeeE]

Birds fly in these mass flocks for protection - the size of the flock can intimidate some predators and it also makes it more diffcult for a predator to focus upon and pick out a specific target.

For the flock to be effective, it needs to have a degree of unpredictability about it, but at the same time the flock needs to stick together to work.  Each bird only monitors the relatively few number of birds immediately around it, so when the front of the flock changes direction it has to propogate through the flock, which is how the 'wave' effects occur.  The birds have probably evolved so that which ever bird is in the lead of the flock instinctively knows it can only change direction by a limited amount, which the rest of the flock will be able to follow, before it risks losing the flock, and therefore it's protection.

It might seem incredible that they can monitor and change direction so quickly but it's probably not much more difficult than flying in to a tree, picking out, and then landing on a twig, whilst constantly monitoring for predators, all in less than a second or two.

Collisions probably do occur from time to time but they must be rare - evolution wouldn't favour birds that collided.