http://www.youtube.com/watch?v=V-mCuFYfJdI This is from a documentary called Earthflight from BBC One and it's narrated by David Tennant (aka the 10th Doctor on Doctor Who). This clip is really cool and explains why raptors don't have an easy time grabbing a starling in a large flock (aka murmuration).

It looks pretty awesome and not nearly as cheesy as that Mississippi River of Death I got from Nat Geo.