Have you ever wished you were a falcon, soaring in great heights and diving steeply at high speeds? How about being an eagle, rising mightily above the prairie? For the longest time, most of us ruefully watched birds as they ascend to the sky through their wings. However, you might be surprised that there are over 60 extant species of birds that can’t fly. Do you think they’re envious of their cruising cousins? What’s the deal with having wings when they can’t use them?
Flightless birds all scattered across the globe, from the kiwis of New Zealand, the penguins in the Antarctic to the ostriches of Africa. And, ratites, such as the Emu, Rhea, Cassowary, Kiwi, and the Ostrich, consists many of flightless bird species. There are also birds from other families, like the rail in the South Atlantic Ocean’s Inaccessible Island and Waka Bird of New Zealand, another specie from the rail family.
There have been many arguments for many years if these flightless birds were actually able to fly. Fortunately, studies divulging into the DNA makeup of both extinct and extant species discovered that flightless birds came from their freewheeling ancestors. That is a case of convergent evolution, where various bird species on different parts of the planet lost the ability of flight by evolving independently.
The ability to fly undeniably provide amazing benefits, such as travelling great distances for hunting and food, migrating and even for escaping their predators. But, there are no pitfalls to flight, like it limits how heavy a bird can weigh, and how big it can grow. Plus, flying surely takes a significant amount of energy.
Nevertheless, the lack of flight is filled up by another ability. For instance, look at the penguins of Antarctica. They may be flightless, but they evolved to be great swimmers and divers. Thus, allowing them to navigate well in the ocean and hunt for fish for food. Meanwhile, ostriches evolved to be great runners, while Kiwis are blessed with an incredible sense of smell, having nostrils at the end of their beaks.
However, researches have proved that it’s a give-and-take situation. You can’t have it all and be a great flier and a fantastic swimmer at the same time. As penguins made headway in their swimming and diving skills, their bodies started to adapt and change. They started growing more prominent, but their wings began developing shorter. Soon enough, their body makeup completely shut out their ability to fly.
Meanwhile, other birds lost the ability of flight just because they no longer need the capability to do so. As the era of dinosaurs came to an end, some aerial animals, mostly birds, started foraging on the ground, as there is no more threat from predators. Soon enough, these birds got larger through the generations and adapted to its new life with lots of free lands. Eventually, they lost the ability to fly and became the ancestors of the ostriches we have today.
On the other hand, the streamer ducks of South America lost the ability of flight because of the abundance in the food supply. With that, they don’t need to travel great distances and hunt for food. Given that there are instances of scarcity in food, streamer ducks are still in a win-win situation as flightless living implies that they don’t need much nutritious food source.
With evolution coming in, it’s not the ability to fly has changed for these flightless birds. While their soaring relatives are blessed with lighter, hollow bones for flight, flightless birds developed denser ones. Moreover, they evolved to have smaller wings but are boasts with bigger bodies, stronger muscles, and sturdier legs, proving that evolution will always seek for the betterment and the survival of the specie wherever it is possible.
Flightless Bird (Wikipedia)
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