Mysterious UFO hunt in Wiltshire, UK

This video was sent to me on April 18, 2021 from Wiltshire, UK with the title Alien Object in England.
Interestingly, many photos and videos of this UFO were also published in Ireland, Wales, Scotland.
In 2017, a similar UFO was observed in Adelaide, Australia. In 2019, a similar UFO was hunted in Hungary.
I talked to my ufologist friend in London about this strange bird object. He expressed two theories.The first theory may be the British Army's covert projects
The second theory may be a robotic bird sent from a spaceship to Earth remotely like a drone.But the London ufologist and I agreed that this object does not belong to humans. The type of flight that this UFO has is completely different from ground technology.
Conclusion The UFO flew at low altitude at a slow speed, so it was searching for an important object.We are not alone.