Did the kiwi ever fly?
Anthony from Room 5 at Halsey Drive Primary School wanted to know did the kiwi's ancestor fly. Matt Rayner, Curator Land Vertebrates, explains the evolutionary history of our national bird.
Thanks for your really interesting question: "did kiwi ever fly?"
In the famous Māori legend "how the kiwi lost its wings" it was the brave kiwi who gave up its wings at the request of Tanemahuta, god of the forest, to save the forests from a plague of nasty bugs that were eating everything in sight.
However for a long time scientists believed that kiwi never lost their wings but evolved from a flightless ancestor that walked onto ancient New Zealand prior it drifting away from Gondwanaland (an ancient mega continent) about 80 million years ago.
This idea has been turned on its head recently when scientists used DNA to discover that kiwi are most closely related to the extinct elephant birds of Madagascar. Given the remote island of Madagascar is on the other side of the world from the remote islands of New Zealand, it appears the ancestor of both elephant birds and kiwi could fly long distances and disperse to new areas.
But who would want to lose their ability to fly? I sure wouldn't. Well it turns out flying uses lots and lots of energy. If you have ever been overseas on a plane ask your mum or dad how much it cost … their answer will be it costs a lot of money! The reason for this is because of all the fuel the plane has to use to stay in the air. Well it's the same for birds.
Now think of the ancestor of the kiwi landing in New Zealand. There's lots of food on the ground and there are absolutely no mammal predators such as cats or dogs or rats that hunt on the ground. Instead the only predators in New Zealand were flying ones like eagles and owls. So to save energy and avoid getting eaten for dinner by some giant big owl, Kiwi adapted towards flightlessness and came out only at night when it was safer.
Post by: Matt Rayner
Matt Rayner is a conservation biologist who specialises in the study of avian behaviour, ecology and evolution. With a particular interest in the Pacific seabirds, he works on closely with conservation and advocacy groups in Australasia and the Pacific through his role as Curator of Land Vertebrates and as a research associate of the University of Auckland. Read Matt's profile.
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