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There are 60 species of flightless birds on Earth today, but a new study finds there would be at least four times as many if it weren’t for human influences.
These findings were discovered by a team at the University College of London who compiled a list of all bird species known to have become extinct since humans first appeared on the planet.
A total of 581 species of birds have become extinct since the Late Pleistocene, 126,000 years ago, and 166 of them lacked the ability to fly.
The study determined that flightless birds thrived on most island groups around the world, with particular hot spots in New Zealand and Hawaii.
The researchers also determined that birds that were unable to fly were more likely to become extinct than those that did fly because they were easy for humans to kill.
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There are 60 species of flightless birds on Earth today, but a new study finds there would be at least four times as many if it weren’t for human influences. This image shows a group of Moari who have gone missing due to the humans hunting them down
Lead author Dr Ferran Sayol (UCL Biodiversity and Environmental Research Center and University of Gothenburg, Sweden) said: “Human impacts have dramatically changed most ecosystems around the world and have caused the extinction of hundreds of animal species.
“This can skew evolutionary patterns, especially if the characteristics studied, such as the inability to fly in birds, make species more vulnerable to extinction. We get a biased picture of how evolution actually happens.
For the study, the team created a long list of all known birds that have lived and become extinct over the past 126,000 years.
Then they sifted through each of them, calculating how many of them were unable to fly in the sky.
For the study, the team created a long list of all known birds that have lived and become extinct over the past 126,000 years. Then they sifted through each of them, calculating how many of them were unable to fly in the sky.
Of the 581 species of birds, the team reduced the number of flightless people to 166 – who may still have roamed the Earth if not for humans.
Birds that cannot fly were much more diverse than previous studies assumed, according to the study.
The results also confirm that species that could not fly were also much more likely to become extinct than species that could fly.
Co-author Prof Tim Blackburn (UCL Biodiversity and Environmental Research Center and Institute of Zoology, ZSL) said: “Many species of birds can become unable to fly in environments without their usual predators, for example on islands.
“Flight spends a lot of energy that birds can use for other purposes if they don’t need to get fresh air. Unfortunately, that makes them easier prey if humans – and their associated rats and cats – suddenly show up.
Birds that cannot fly were much more diverse than previous studies assumed, according to the study. The results also confirm that species that could not fly were also much more likely to become extinct than species that could fly.
“Extinction has too often been the result of this, and it is likely to continue as flightless birds are overrepresented, relative to avian species, on global lists of endangered animals.
Researchers report that most island groups around the world had flightless birds before humans arrived, occupying ecological niches that otherwise would have been filled by mammals, with particular hot spots in New Zealand ( 26 species such as the extinct moa) and Hawaii (23 species, all of which are extinct, such as the flightless goose).
Adding extinct birds to the overall picture of bird diversity reveals that inability to fly evolved in birds at least four times more often than we would expect if we were only looking at live birds .
Dr Sayol said: “Our study shows that the evolution of flightlessness in birds is a widespread phenomenon.
“Today, most of the flightless species are penguins, rails or ostriches and their parents.
“ Today, only 12 bird families have flightless species, but before humans caused extinctions, the number was at least 40. ”
“Without these extinctions we would share the planet with flightless owls, woodpeckers and ibises, but all are now sadly gone.
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