Bird extinction

Perhaps one of the most widely recognized extinct bird species is the dodo.[1] It was a plump, flightless bird that lived solely on the island of Mauritius in the Indian Ocean. With abundant food and no predators on the island, their descendants evolved & grew heavier and bigger, their beaks grew larger, and their wings smaller. Its limited range, inability to fly, and lack of exposure to and fear of humans contributed to its rapid extinction. Humans in the 17th century took advantage of its fearlessness and flightlessness by killing them in their hundreds as a food source for sailors.[10] The dodo likely became extinct before it was fully described by taxonomists.[11] Its sudden extinction highlights the susceptibility of endemic island species, and the dodo serves as an early poster species for anthropogenic extinction.

The great auk (or, as it has been nicknamed, the “Penguin of the North”[12]) was a flightless marine bird that inhabited the cold North Atlantic ocean and islands. Its range once extended to the continental United States and Europe. However, by the 1800’s had a very limited range, breeding only on a few rocky islands in the North Atlantic.[13] It was targeted by hunters for its prized skin. Hunters took advantage of the great auk's breeding season, when pairs nested in large colonies on rocky islands.[14] It was much more difficult to hunt when not breeding, as birds were less concentrated and spent most of their time in frigid waters, where they were fast swimmers. The last accepted sighting of the species alive was in 1844, when a breeding pair was found and strangled by hunters hoping to sell the sought-after skins.[15]

A more contemporary bird extinction was that of North America's passenger pigeon. It was a flocking species that once occurred in great densities. Prior to the arrival of colonial Europeans in North America, the passenger pigeon was thought to account for up to 40% of all individual birds on the continent.[16] It was declared extinct in 1914, with the death of the last known survivor of the species, Martha, at the Cincinnati Zoo. However, it had not been seen in the wild for nearly 20 years prior to Martha's death.[17] The main drivers of the species extinction were habitat destruction and hunting. The habitat destruction was also related to the invasive chestnut blight, which greatly reduced the number of American chestnut trees in North America.[18] The passenger pigeon is one of the few recently extinct bird species that has been proposed for “de-extinction”.[19] The entire genome of the species has been sequenced from surviving tissue with the hope of being able to bring it back onto the landscape using novel genetic techniques. However, birds are more complicated physiologically than mammals, which presents practical difficulties to the process of de-extinction.

In June 2020 the Royal Society of South Australia published a list of 95 Australian bird fossils. The list includes three species of huge flamingos from the Kati Thanda-Lake Eyre and Lake Frome areas of South Australia, which were estimated to inhabit the area for 25 million years before becoming extinct about 140,000 years ago, most likely from drought. There were also penguins measuring about 2 metres (6 ft 7 in) tall, which lived between about 60 million and 30 million years ago, dying out in the Oligocene. Researcher Trevor Worthy said that little was known about the evolution of birds in Australia, which stands at about 1,000 species.[20][21][22]