The approach builds on a single-drone navigation technique, which rapidly maps routes around obstacles as they come within view using only the drone's onboard camera and computer. The team, which was also behind the earlier strategy, adapted it for swarms by getting drones to broadcast their trajectories over a wireless network. That allowed the other drones to choose routes that avoided collisions while staying in formation.
I'm sure it works, though the publication's definition of "heavy forest" is a bit generous. The video is basically the drones navigating a few trees behind a building. They get the job done in the video, but who knows how well this would work in an actual heavy forest. I'm hopeful though, since this technique might be our best shot at finally finding Bigfoot or my lost stash of porn.