Items13The creator’s order
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Common ostrichAn ostrich holds its wings out for balance when it runs and turns. Its long legs and two-toed feet do the work of crossing open ground. Evolutionary studies place the ostrich among several lineages of large birds that lost flight independently, a better explanation than a single flightless ancestor…0 - 2
Emperor penguinAn emperor penguin propels itself underwater with wings shaped like stiff flippers. One explanation for the loss of flight in penguin ancestors is that a wing built for efficient swimming becomes costly to use in air. Biologists tested that idea by measuring energy use in diving seabirds that can…0 - 3
Flightless cormorantThe Galápagos flightless cormorant has much smaller wings than its flying relatives. It chases prey underwater and gets its thrust from its feet. A study comparing the bird with its flying relatives found clues to reduced wing growth, adding another line of evidence alongside the skeleton.0 - 4
KākāpōThis New Zealand parrot climbs trees and uses its wings to balance and slow its descent. Lighter birds can manage a short glide. That leaves the kākāpō with more options than staying on the forest floor, even though it cannot sustain powered flight.0 - 5
EmuAn emu has long legs and wings shorter than eight inches. In much of Australia it can cover great distances on foot in search of food and water. Comparisons of developing ostriches and emus found different patterns of wing growth, evidence that two birds can end up grounded in different ways.0 - 6
Southern cassowaryThe cassowary’s tiny wings bear a few long, bare quills. Its legs carry it through rainforest, where it swallows fruit and spreads large seeds. Those are clues to a bird that makes its living on the ground. Its exact route to flightlessness is harder to piece together than its present-day anatomy.0 - 7
Greater rheaA greater rhea has comparatively long wings for a bird that cannot fly. It spreads them for balance and to change direction while running, and males use them in courtship. Compare it with the emu to see how differently wings can look and work after flight is lost.0 - 8
North Island brown kiwiLook at this kiwi and its wings are easy to miss. They are tiny and hidden beneath the shaggy feathers. The bird searches for food mainly at night, probing with a long bill. Unlike most birds, a kiwi has nostrils near the tip, a useful feature when finding food on the ground.0 - 9
TakahēThe South Island takahē is a large rail with short wings. Look for the wings during a courtship or threat display, when the bird spreads them where another bird can see. Its behavior shows that wings can keep a job after a lineage becomes flightless.0 - 10
WekaThis New Zealand rail is flightless, but it can swim. In one observation, weka swam more than half a mile back to an island after being moved. On land, they forage by shifting leaf litter with their bills. Their example makes it easier to see how a flightless bird can still move between islands.0