Birds

Birds
Birds are vertebrate animals adapted for flight. Many can also run, jump, swim, and dive. Some, like penguins, have lost the ability to fly but retained their wings. Birds are found worldwide and in all habitats. The largest is the nine-foot-tall ostrich. The smallest is the two-inch-long bee hummingbird.

Everything about the anatomy of a bird reflects its ability to fly. The wings, for example, are shaped to create lift. The leading edge is thicker than the back edge, and they are covered in feathers that narrow to a point. Airplane wings are modeled after bird wings.

The bones and muscles of the wing are also highly specialized. The main bone, the humerus, which is similar to the upper arm of a mammal, is hollow instead of solid. It also connects to the bird’s air sac system, which, in turn, connects to its lungs. The powerful flight muscles of the shoulder attach to the keel, a special ridge of bone that runs down the center of the wide sternum, or breastbone. The tail feathers are used for steering.

Birds have a unique digestive system that allows them to eat when they can—usually on the fly—and digest later. They use their beaks to grab and swallow food. Even the way a bird reproduces is related to flight. Instead of carrying the extra weight of developing young inside their bodies, they lay eggs and incubate them in a nest.

The fossil record shows that birds evolved alongside the dinosaurs during the Jurassic period 160 million years ago. The best known fossil is archaeopteryx, which was about the size of a crow.

—From the National Geographic

For the kind cooperation, I thank the Nature and Oasi degli Animali Zoom Torino

Conservation
The IUCN REDLIST , established in 1948 is the largest database of information on the status of conservation of every animal and plant species of the Planet. The technical and scientific data are collected and analyzed by many expert zoologists and botanists who lend part of their scientific work to IUCN in a totally free way. THANK YOU!
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Legenda
[NE] NOT EVALUATED:
No evaluation was made
[LC] LEARN CONCERN:
At relatively low risk of extinction
[NT] NEAR THREATENED:
It will probably become vulnerable
[VU] VULNERABLE:
High risk of extinction in nature
[EN] ENDANGERED:
At very high risk of extinction in nature
[CR] CRITICALLY ENDANGERED:
At extremely high risk
[EW] EXTINCT IN THE WILD:
It survives only in captivity
[EX] EXTINCT:
No surviving individual

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Licenza Creative Commons
Animals In Black di Gian Luca Partengo è distribuito con Licenza Creative Commons Attribuzione - Condividi allo stesso modo 4.0 Internazionale.
Based on a work at https://animalsinblack.it.