1.      Only Birds Have Feathers

Birds are the only animals in the world that have feathers. Feathers are important for flying, but that was not what they were originally used for. As strange as it may seem, birds are the descendants of dinosaurs that evolved feathers to help their bodies conserve heat. It was only later that these avian animals began using feathers for flying. Today, birds still use their feathers to help control their body temperature and to fly, but they have many other important uses as well. Birds use their feathers to communicate with other birds, as camouflage to keep them safe from predators, and even as a soft material to line their nests with.

2.      Not All Birds Can Fly

While all birds have feathers, not every species of bird uses their feathers to fly. You see, flying requires large muscles and a great deal of energy. Because of this, flightless birds do not need nearly as much food as a flying bird does. These birds can survive in harsher environments where food may be harder to come by. For example, all 18 species of penguins cannot fly. Instead, their bodies have evolved for diving and skillful swimming. Gentoo penguins, for example, can swim through the water at speeds up to 22 mph! There are many other kinds of flightless birds as well, like New Zealand’s kiwi and kakapo. The ostrich cannot fly, but instead they can run up to 45 mph! Then there is the giant Australian cassowary—these behemoth birds may not be able to fly, but they can run up to 31 mph and jump 7 feet into the air.

3.      Birds Have Hollow Bones

Flying take a lot of strength and energy, especially if a bird is going to remain airborne for long periods of time. To help reduce stress on their bodies, bird skeletons have evolved over time to have modified, hollow or partially hollow bones. Hollow bones have air spaces inside that help the bird’s body to absorb more oxygen and give them more energy for flying. They are also much lighter than solid bones. In fact, a bird’s feathers weigh more than its entire skeleton does! However, bird skeletons are still strong enough to support the bird’s body while flying, landing, and moving on land.

4.      Birds Lay Eggs

Another important requisite for birds is that they lay eggs. The bee hummingbird’s eggs are the smallest, weighing in at only 0.02 ounces and measuring less than 1/5 inch by ¼ inch. An ostrich egg, on the other hand, is the largest egg in the world. Ostrich eggs are 5 inches tall, 5 inches wide, and weigh a whole 3 pounds! However, in terms of bird to egg ratio, the kiwi takes the gold. These birds may only be the size of a domestic chicken, but their eggs are 5 inches long and weigh up to a pound, which is around 20% of a female kiwi’s weight. That would be equivalent to an ostrich laying an egg that weighed 88 pounds!

5.      Birds Come in All Shapes and Sizes

There are around 10,000 species of bird throughout the world, which means there is a lot of variety from species to species. The ostrich, for example, is the largest bird on earth today, growing up to 9 feet tall and weighing up to 350 pounds! The bird with the largest wings is the wandering albatross, with a wingspan that measures nearly 12 feet across. The smallest bird in the world is the bee hummingbird. These tiny birds weigh less than 2 grams and may be only 2 inches long. Then there is the most dangerous bird in the world, the cassowary. While it may look like an exotic ostrich, the cassowary has a hidden weapon that you should steer clear of: its toes. Cassowaries have a sharp claw on each of their middle toes that can grow up to 4 inches long. The combination of brute force and these dagger-sharp claws is lethal and has even been known to kill humans.

6.      Many People Keep Birds as Pets

Birds are smart animals, each with its own individually unique personality. Because of this, many people enjoy taking care of pet birds in their homes. In fact, some estimates report that over 3 million households in the United States own a pet bird. Some pet birds are small, like canaries, finches, lovebirds, cockatiels, and parakeets. Others are large, like African grey parrots, cockatoos, and macaws. Many pet birds can be taught to mimic sounds and even human voices. The famous African grey parrot, Alex, learned over 100 words and could identify numbers, colors, and shapes. Macaws are also extremely social, and many enjoy spending time with their owners. Even smaller birds like budgies and cockatiels can learn to use hundreds of words, are quick to train, and can bond with their owners.

7.      Birds Don’t Have to Worry About their Feet Getting Cold

Unlike many animals—including humans—birds do not lose too much heat through their feet, even in cold winter weather. Their feet still get cold, but it doesn’t seem to bother them too much. This is because there are uniquely structured blood vessels in their feet. When warm blood from the bird’s heart flows into its feet, it passes alongside the colder blood flowing from the feet back up to the heart and helps to warm it back up. In addition, many birds often stand on only one foot at a time, with the other foot tucked nicely into their warm feathers. Other times they will lower their bodies down over their feet, surrounding them with their feathery plumage to keep them warm.

8.      Birds Are the Fastest Animals on Earth

The fastest animal in the world just so happens to be a bird! While cheetahs are the fastest land animals and can run up to 70 mph, peregrine falcons can travel nearly 200 mph when diving down to catch a meal! White-throated needletail swifts, on the other hand, can fly horizontally through the air at speeds up to 105 mph. Albatrosses fly around 50 miles per hour, but these large seabirds can go without touching land for the first 6 years of their lives! However, a male bar-tailed godwit holds the record for longest migration without stopping, having flown 7,500 miles over the Pacific Ocean. Not all birds, however, are quite that fast. In fact, the slowest bird in the world—the American woodcock—flies at a mere 5 mph. And hummingbirds are very unique, because they can hover at 0 mph, and even fly backwards!

9.      Birds Are Smart and Often Use Tools

When Charles Darwin visited the Galápagos Islands in 1835, he noticed that many finches there were using tools to get their food. The woodpecker finch, for example, breaks off small twigs or cactus spines to the length it wants, then uses these to scrape insect larvae from crevices in trees. On New Caledonia in the Pacific Ocean, New Caledonian crows actually bend twigs to make hooks and serrated rakes. And in Japan, carrion crows have been seen dropping nuts on the road for cars to smash open, making them easier to eat. The crows even waited at the traffic light alongside human pedestrians before walking out to the street to collect the now crushed-open nuts!

10. Many Birds Are in Danger of Extinction

Today, at least 11% of bird species are endangered, with more threatened and struggling to adapt to the changing climate. In fact, in North America alone 2/3 of all birds are threatened with extinction. In just the last 50 years, bird populations in Canada and the United States have dropped by more than 29%, or 3 billion birds. The rising temperature of the earth is a large factor, but so is habitat loss, pesticides, and pollution. Birds are continually challenged to find new homes and new territories as humans continue to drain wetlands, destroy forest areas, and contaminate their habitats.

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