LJ,
Most of those videos from the likes of KevinMC360 are birds filmed with infra red.
This is the YT Channel of the person that claimed to have filmed the video in post #1. He also acknowledges that some of his footage is simply birds. There are also a lot of hoaxers out there and the UFO programmes will pay a pretty penny for such footage. A bit of CGI or manipulation of a bird formation and you have a nice little earner.
dede95064 - YouTube
See from 0:47 on the KevingMC360 video as featured in the Daily Mail link.
YT is full of 'UFO' hunters trying to pass off infra red footage of birds as 'squadrons of UFOs. KevinMC360 thinks that they are fighting battles!
As you can see birds also make interesting shapes even on radar!
Fig. 1. A single frame of the 8-ram film used to record radar data. Arrow points to a group of geese flying in a V. Diameter of the area shown in radar display 1.85 km. Other radar echoes are from objects on the ground (primarily trees andfarm fences).
Image link
http://files.abovetopsecret.com/imag...be2c05b97b.jpg
From
http://elibrary.unm.edu/sora/Auk/v09...0554-p0559.pdf