What bird is this?

Sorry I can barely see a bird never mind identify it!

Sorry, my friend filmed it on his phone and we couldn't get any closer at the time. But going by what I saw at least, I can say there were about 5/6 of them swooping down in the fields below (almost seemed like courting or playing). They were black on top with a white underside, had the appearance of a bird of prey, and gave off a distinct slide-whistle sounding call. If you wait until 17 seconds into the video you should just be able to hear them.

Hey no worries, could be lapwings but maybe someone else more experienced could confirm.

Could be Lapwing

It was hard to tell if they looked the same at a distance, but going by sample videos on YouTube they do sound very similar. Much appreciated

Not a problem.....maybe yous will get a bit closer next time for a better look