Attenborough's Big Birds (2015)

Meet the big birds, a feathered family who have never flown a day in their lives! From ostriches to kiwis, these bizarre birds appear to be nature's greatest novelty act. How they came to be and how they continue to survive is a fascinating tale that has long captivated Sir David Attenborough. It is a story of dedicated dads, enormous eggs and a serious need for speed. And far from being the court jesters of the animal world, these flightless curiosities once nearly ruled the land.

Unfortunately the movie Attenborough's Big Birds is not yet available on HBO Max.