This reminds me of a sitcom In the later half of the 1960s about an inept spy named Maxwell Smart that used a similar device, but for a different reason. Every time Mr Smart and his boss were having a secret conference in the bosses office, a clear plastic box called the “Cone of Silence” would descend from the celling and cover their heads to prevent others from hearing the conversation. https://youtu.be/g1eUIK9CihA
The Audubon Society article I read stated the birds kill "Millions of song Birds a year in the UK.