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People might wonder why some birds have wings but don't use them and maybe see it as a strange evolution, or that the birds haven't evolved appropriately.
It's actually the opposite. The theory goes that the birds evolved to become flightless due to a lack of predators where they lived. They didn't have many enemies, so didn't really need to escape.
We've picked three videos of our favourite flightless birds for you, so enjoy!
1. Kagu
While this young kagu might not enjoy the meal it is being given we hope it's grown up to be the pale grey ground-living bird with a funny walk just like its parents. Kagus do use their patterned wings for displays and gliding, but their primary way of getting around is to run extremely fast over short distances before standing stock-still and doing it again.
2. Penguin
Penguins may be birds but sometimes they resemble fish more closely having adapted to live in the cold ocean water of the Southern Hemisphere. But despite their amazing ability to swim, using their wings like flippers, one penguin parent will walk 250 miles in search of food while the other guards the young chick.
3. Kakapo
This adorable, peaceful and record-breaking bird is unfortunately almost extinct. Living exclusively in the forests of New Zealand, these green birds sit motionless in the treetops, using their wings for balance.
Their green feathers provide excellent camouflage - only the blink of an eye would give them away. They also have incredible climbing ability, as you can see in this great video.