Giant flocks of birds

For some reason there's this huge flock of birds that's been around a lot.  I'm guessing it has 50,000 birds in it.  There's maybe 200 in this picture

but imagine 2,000 feet of this, and you've got a better idea of the size of this flock.  I think they're starlings. 

I'm glad that they're around; there's a peregrin falcon that's been eating them and with plenty of natural game around I'm hoping my chickens aren't on the menu.