My personal pasttime is watching wildlife films for how they were done!
BBC knows all places where wild animals were tamed by scientists or reserve managers around the world. That is how many photos are made. Also, big series like "Life of birds" is a teamwork of many photographers sending footage from all over the world. Sir David himself did not visit all the birds shown. Nest close-ups are camera buried in grass near the nest. Some footage shows captive animals. Usually all longer scenes (like predator chasing prey) are composed from many different footages.
EG. you might notice that when egret catches fish (filmed from below), the remaining fish don't swim away. Egret is picking them from small aquarium or jar put above the camera.
Falcons chasing birds are veery problematic, I remember somebody arguing that they were composed not just from different hunts, but the falcon itself changed species several times in "one hunt".
When Goshawk catches a bird, note how the angle of camera changes. It is a tame bird whizzing just in front the cameraman from one side to another. Then the Goshawk lands in the middle of open meadow. The next scene shows a close-up of it. Nobody can creep in short grass until 0,5 m from the hawk. Yes, a tame bird again.
Some auks swimming underwater are in artifical light with solid rocky backdrop. Aquarium tank. Notes at the end allows you to read, that this was Cincinnati Zoo.
Happily, in this series you don't see many concrete rocks, gardener plants, blocked backdrops and other signs of zoo/cage photography.
"Life of birds" is actually much less edited than Attenborough earlier films, and certainly much more faithful than eg. Jeff Corwin with mostly tame animals. But looking carefully, you will still notice a lot!
