Birds are warm-blooded vertebrates belonging to the class Aves. Their unique features include feathers, toothless beaks, and hard-shelled eggs. In addition to their feathers, birds are also notable for their high metabolic rates, four-chambered heart, and strong lightweight skeleton. Learn more about birds to get a better understanding of this fascinating group of animals. Read on for the characteristics of some of the most commonly known birds.
The word bird has long been a cultural resource. Prehistoric humans in France created bird figures in the Lascaux Grotto. Since ancient times, birds have featured in mythology and literature throughout the world. Their knowledge of and interest in birds was recorded in stories and conversation. Even ancient Egyptian hieroglyphs contain bird figures. These symbols illustrate the diversity of birds in our world. And as you can see, birds have been around for quite some time.
While some birds have evolved over time, others remain unknown. The earliest avian forms resemble our modern birds, such as penguins and ostriches. Their ancestors were toothless, and many species of birds evolved after the Cretaceous period. Modern birds include ostriches, penguins, storks, ducks, hawks, and cuckoos. Unlike other mammals, birds do not carry developing young in their bodies, instead they lay eggs.
The skeleto-muscular structure of birds allows birds to combine light weight with high power for flight. The majority of the body is made up of muscle mass concentrated around the body’s center of gravity and at the bases of wings and legs. These muscles are regulated by long tendons. Some flighted birds have bigger breasts and wing muscles than their terrestrial counterparts. The flexor muscle tendon is situated behind the ankle.
Avian ecology has led to the rapid diversification of birds. From single-celled stragglers on polar ice caps to complex communities living in tropical forests, birds can be found virtually anywhere on Earth. Geographical distribution of bird species is influenced by a variety of factors, including climate, habitat availability, presence of predators and food. Breeding areas differ from nonbreeding areas, and seasonal movements and migration routes are important factors in determining total number of species.
The feathers on birds’ bodies are similar to those of mammals. Unlike mammals, birds do not have sweat glands. Instead, they use panting to release heat and lower their metabolic rate. Birds may also seek shade or raise their feathers in order to catch a breeze. Besides being lightweight, their feathers provide a protective covering for the body. A few species of birds do not have a respiratory system, and some even lack it entirely.
Another way to identify birds is through sound recordings. The Macaulay Library at the Cornell Lab of Ornithology offers more than 30,000 sound recordings of birds. It also features identification tips in various languages. If you have never heard of a bird before, this free program is the perfect companion for birdwatchers. It can help you build a life list. If you have ever seen a bird you didn’t recognize, you can learn about it by listening to its songs and calling.