This is not a new discovery , nor does the linked article claim it is.
Rather, it says that "Precision formation flight astounds scientists."
Which is to say, scientists have finally gathered the necessary proof to overcome their long-standing skepticism about something that has long seemed obvious to birdwatchers, aerospace engineers, computational aerodynamicists, and pilots - that the V-formation exploits tip vortices and other dynamic flow phenomena to improve flight efficiency.
Apparently, (acto this report, anyway) some scientists doubted that birds actually had the sensory abilities and precision-flight capability necessary to actually do what all the computational models suggested they were doing.
But they do. And apparently, that leaves some long-skeptical scientists 'astounded.'
Meanwhile, many of the rest of us are astounded that they doubted it in the first place.
But hey, that's science for ya.