Birds also have more cervical (neck) vertebrae than many other animals; most have a highly flexible neck that consists of 13-25 vertebrae.
Unfortunately, hunting, destruction of habitat, and pollution have also caused many birds to be placed on lists as endangered or threatened species.
Birds' high metabolism requires rapid circulation because of the quick build up of waste products, and need for oxygen.
Birds range in size from the tiny hummingbirds to the huge ostrich and emu.
The list of birds gives a more detailed summary, including families.
Some birds have a crop, which is a storage pouch that is part of the esophagus and can allow birds to feed and store food until later digestion.
Modern birds are classified in the subclass Neornithes, which is further separated into two superorders, the Paleognathae (mostly flightless birds), and the wildly diverse Neognathae, containing all other birds.
Birds have adapted to virtually every part of the globe and a wide diversity of habitats: forests, grasslands, cities, mountains, deserts, wetlands, and oceans.
The ?-keratins used by birds and reptiles are even tougher than the ?-keratins of mammals.
Birds are a very differentiated class, with some feeding on nectar, plants, seeds, insects, rodents, fish, carrion, or other birds.
Birds also generally have a faster heart rate and a greater need for oxygen than mammals, and have a higher metabolic rate.
Birds have four-chambered hearts, and a circulatory system with blood vessels.
The three mating systems that predominate among birds are polyandry, polygyny, and monogamy.
The majority of birds are monogamous and many species mate for life, reflecting the higher aspirations of the human spirit and religion.
Most of these, about 150 species, are duck like birds, as well as a small number of grebes (20), loons (4), penguins (15), and auks (21) (Mayr 2001).
The use of gizzard stones appears to be a similarity between birds and dinosaurs, based on trace fossils of gizzard stones called gastroliths.
Smaller birds generally have a higher metabolism than larger birds, and have relatively higher energy needs.
The only animals covered with feathers, most birds are characterized by flight.
Some birds even feed on parasites on black rhinoceroses, or within the mouths of crocodiles.
The high metabolism of birds necessitates an effective system for acquiring a great deal of oxygen.
Colorful, particularly tropical, birds (e.g., parrots, and mynahs) are often kept as pets although this practice has led to the illegal trafficking of some endangered species.
Other animals have wings and can fly, such as bats, but only birds are covered with feathers.
Egyptians also included birds among their gods, and the ibis was often mummified and placed in the tombs with royalty.
The ratites are large flightless birds, and include ostriches, cassowaries, kiwis, and emus.
Birds (class Aves) are bipedal, warm-blooded, oviparous (egg-laying) vertebrates characterized primarily by feathers, forelimbs modified as wings, and a bony beak without teeth.
The number of hollow bones varies from species to species, though large gliding and soaring birds tend to have the most.
Throughout the ages, birds have been integral to human culture, whether as food, pets, bird products, or inspiration for paintings, literature, and religion.
Many birds migrate long distances to utilize optimum habitats (e.g., Arctic tern), while others spend almost all their time at sea (e.g., the wandering albatross).
Birds are both endothermic (create their own heat) and homeothermic (maintain a constant internal temperature).
The path of humans and birds have intersected in many ways throughout human culture, whether directly through hunting and domestication, or as powerful symbols in literature, arts, and religion.
Color patterns serve as camouflage against predators for birds in their habitats, and by predators looking for a meal.
After the eggs hatch, parent birds provide varying degrees of care in terms of food and protection.
Birds are also prominent in the Bible, with over forty species of birds mentioned.
Most birds have a stomach made of two parts, the first part, or proventriculus, which secretes digestive fluids, and the second, the gizzard.
One, the thecodont theory, is that birds arose from archosaurian reptiles sometime before the Upper Jurassic (around 135 to 160 million years ago), perhaps in the late Triassic more than 200 million years ago.
Birds have also provided products for use in human societies, such as feathers and skins.
Some birds, such as the owls and nightjars, are nocturnal or crepuscular (active during twilight hours).
One explanation for the high rate of monogamy among birds is the fact that male birds are just as adept at parental care as females.
Many birds seasonally migrate long distances, improving opportunities for food, better climate, and breeding.
Polygyny (one male with more than one female) constitutes 2% of all birds, and polyandry (one female with more than one male) is seen in less than 1%.
Many waterfowl and some other birds, such as the ostrich and turkey, do possess a phallus.
Birds have many bones that are hollow, with criss-crossing struts or trusses (cross walls) for structural strength.
Some, such as frigatebirds, stay aloft for days at a time, even sleeping on the wing.
Sibley and Ahlquist's Phylogeny and Classification of Birds (1990) is an often cited work on the classification of birds, but is also frequently debated and constantly revised.
Birds ventilate their lungs by means of crosscurrent flow: the air flows at a 90° angle to the flow of blood in the lungs' capillaries.
Birds are the only vertebrate animals to have a fused collarbone (the furcula or wishbone) or a keeled breastbone (or sternum).
Other birds that have been utilized for food include emus, ostriches, pigeons, grouse, quails, doves, woodcocks, songbirds, and others, including small passerines, such as finches.
Common characteristics of birds include the laying of hard-shelled eggs, high metabolic rate, and a light but strong skeleton, generally with hollow bones.
Eminent evolutionist Ernst Mayr (2001) notes that this species has so many advanced avian characters that the original birds much have existed considerably earlier.
The chicks of many ground-nesting birds, such as partridges, chickens, and waders, are often able to run virtually immediately after hatching; such birds are referred to as nidifugous.
Precocial birds—those that are relatively mature at birth—can care for themselves independently within minutes of hatching.
The list of birds gives a more detailed summary, including families.
The pectoral (breast) muscles of birds are the largest, and may account for 20% of a bird's weight.
Some birds even feed on parasites on black rhinoceroses, or within the mouths of crocodiles.
The path of humans and birds have intersected in many ways throughout human culture, whether directly through hunting and domestication, or as powerful symbols in literature, arts, and religion.
Flightless birds include the penguin, ostrich, kiwi, and the extinct dodo.
Flamingos and doves are more closely related than they look, a new genetic analysis of birds shows. That's not all: chickens are close relations of dinosaurs, and genetic patterns in the brains of birds that learn new calls show remarkable similarities to humans.Dec 11, 2014
Birds mostly use their keen eyesight to find food. They use their beak and their claws to get bugs , worms , small mammals , fish , fruit , grain, or nectar . Birds play a very important part in the natural control of insects and in the dispersal of seeds.
Birds are obviously important members of many ecosystems. They are integral parts of food chains and food webs. In a woodland ecosystem for example, some birds get their food mainly from plants. Others chiefly eat small animals, such as insects or earthworms.Nov 29, 2012