On the noise:

> "Given this video is taken by a drone, and drones are very noisy..."

Here's from National Geographic's press release on this video:

“Through the harnessing of new technology and pushing the boundaries of polar filming, Bertie utilized a newly released camera drone equipped with a telephoto lens allowing him to capture animal behavior from the air like never before without disrupting or impacting the penguins.”

https://www.businesswire.com/news/home/20240411040454/en/Nat...

So they were aware of the noise and other disturbance to the penguins, and were far enough away its unlikely these sounds are recorded from the drone itself.

On the audio track:

Mics and recorders could have been placed in advance. Given the level of preparation described, this is a possibility.

Audio of a given action or situation could have been captured separately elsewhere and dubbed. This seems most likely, and if natural sounds were captured on location from the same flocks, wouldn't generally carry a disclaimer.

In either of these cases, the drone doesn't need a mic, or can carry one just for sound sync purposes, but the sound is done in foley with or without a field recording.

To use drone audio without it audible to the viewer, shotgun mics with a sound pattern that picks up far point noise (imagine a teleaudio mic to go with the telephoto lens) could be used.

Drone noise is distinct, and can be removed, firms and software specialize in this: https://www.sound2design.com/online-sound-restoration-and-dr...

One way is to point the shotguns at silence, record drone noise alone, then invert it, something like "speech transparency" mode in noise cancelling headphones.

Today's audio processing is relatively magical when it doesn't have to fit in an earbud.

I haven't researched this case, but it sounded like foley.