Birds (class Aves) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. About 10,000 living species inhabit ecosystems all over the globe, and range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) ostrich. Birds emerged within theropod dinosaurs around 150 million years ago during the Jurassic period, and are the only members of the clade originating with the earliest dinosaurs to have survived the Cretaceous–Paleogene extinction event 66 million years ago.
Modern birds are characterized by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All living species of birds have wings and most can fly, but not all of them (e.g. penguins and ostriches). Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.
Bird eyes possess green, red and blue cone cells, as well as ultraviolet (UV) sensitive cells which allows them to perceive ultraviolet light. Many birds look unremarkable to humans, but in ultraviolet light patterns emerge that are invisible to the human eye. Birds have one of the most complex respiratory systems of all animal groups. Upon inhalation, 75% of the fresh air bypasses the lungs and flows directly into a posterior air sac which extends from the lungs and connects with air spaces in the bones and fills them with air. The other 25% of the air goes directly into the lungs. When the bird exhales, the used air flows out of the lung and the stored fresh air from the posterior air sac is simultaneously forced into the lungs. Thus, a bird’s lungs receive a constant supply of fresh air during both inhalation and exhalation.
Many bird species migrate across deserts and oceans without refueling to take advantage of global differences in seasonal temperatures. Landbirds have a flight range of around 2,500 km (1,600 mi) and shorebirds can fly up to 4,000 km (2,500 mi), although the Bar-tailed Godwit is capable of non-stop flights of up to 10,200 km (6,300 mi). Seabirds also undertake long migrations, the longest annual migration being those of Sooty Shearwaters, which nest in New Zealand and Chile and spend the northern summer feeding in the North Pacific off Japan, Alaska and California, an annual round trip of 64,000 km (39,800 mi).
Red Lory (Eos bornea or Eos rubra)
(PHOTO: Doug Janson)
The Red Lory hails from the tropical forests of Indonesia. In addition to its colorful appearance, this bird has an outgoing and flamboyant personality and is highly intelligent. In the wild, Lories eat nectar, pollen, fruits, and occasional insects.They requires lots of attention and care when kept as pets. Red Lories should be given toys (ropes, bells, balls, swings), chewing items and branches. They need to be bathed frequently, and they can be dried by the sun or with a blow drier. A moderate amount of feathers must be clipped regularly to prevent them from flying. Lories are very trainable, affectionate, playful and curious and they can display some interesting behaviors. For example, some lories have wrapped themselves in a washcloth for sleeping; some sleep on their backs with their feet up in the air.
Female Peahen (Pavo cristatus)
The Peacock is also known as the Indian Peafowl or Blue Peafowl. It is a large bird from the pheasant family native to South Asia, but introduced and semi-feral in many other parts of the world. The male peacock is predominantly blue with a fan-like crest of spatula-tipped, wire-like feathers and is best known for the long train made up of elongated upper-tail covert feathers which bear colorful eyespots. These stiff and elongated feathers are raised into a fan and quivered in a display during courtship. The female (peahen) lacks the train, has a greenish lower neck and a duller brown plumage. Peacocks forage on the ground in small groups for berries and grains, but they will also prey on small snakes, lizards, and small rodents. They are fond of dust-bathing and at dusk, groups walk in single file to a favorite waterhole to drink. Their loud calls make their presence easy to detect, and often indicate the presence of a predator such as a tiger. Peacocks will usually try to escape predators on foot through undergrowth and avoid flying, though they will fly into tall trees to roost at night.
The birds can be a nuisance to agriculture and gardens, as they damage crops. The adverse effects on crops seems to be offset by the beneficial role they play by consuming prodigious quantities of pests such as grasshoppers. Peacocks are generally a pain in the ass around homes: not only do they damage plants, they attack their reflections breaking glass and mirrors, perch on and scratch up cars, and leave their droppings everywhere.
African Penguins (Spheniscus demersus) are also known as Black-footed Penguins, and are native to South African waters. Like all penguins it is flightless, with a streamlined body, and wings stiffened and flattened into flippers for a marine habitat. Adults weigh on average 2.2–3.5 kg (4.9–7.7 lb) and are 60–70 cm (24–28 in) tall. The bird has distinctive pink patches of skin above the eyes and a black facial mask, along with black feet. African penguins have a black stripe and black spots on the chest, the pattern of spots being unique for every penguin, like human fingerprints.
The African Penguin is monogamous. Parents are protective of their hatchlings, but will not sacrifice their appetite for their children: in a situation where food is scarce, adult parents will let their children starve before they let themselves starve.
The species is endangered: of the 1.5-million African Penguin population estimated in 1910, only some 10% remained at the end of the 20th-century. African penguin populations, which breed in Namibia and South Africa, have declined by 95 percent since preindustrial times. Threats also include pollution of their habitat by petrochemicals from spills, shipwrecks and cleaning of tankers while at sea. Commercial fisheries have forced them to search for prey farther off shore, as well as making them eat less nutritious prey, since their preferred prey has now become scarce. Global climate change is also affecting these penguins’ prey abundance. If the population decline is not halted, the African Penguin is expected to be extinct within 15 years.
Also known as the Tiger Owl, the Great Horned Owl is a large owl native to the Americas. Its “horns” are neither ears nor horns, just tufts of feathers. Wild owls have a maximum recorded lifespan of 13 years; in captivity they may live for up to 38 years. The eyes of a Great Horned Owl are nearly as large as those of a human being. They have spectacular binocular vision, allowing them to pinpoint prey and see in low light. As you can see from the picture of Earl here, the Great Horned Owl’s iris is yellow, except in the amber-eyed South American Great Horned Owl (B. V. nacurutu). An owl’s hearing is as good as, if not better than, its vision.
These owls also have approximately 300 pounds per square inch (PSI) of crushing power in their talons. Almost all prey is killed with the owl’s talons, often instantly, though some critters may be bitten about the face as well (!!!). Prey is swallowed whole whenever possible. The Great Horned Owl will prey on pretty much any living creature that walks, crawls, flies, or swims, except large mammals—although it will happily prey on mammals two to three times heavier than itself such as porcupines, marmots and skunks. (In one case, the remains of 57 striped skunks were found in a single owl nest.) Hares and rabbits are statistically the most regular prey, but the birds also snack on small to moderately sized rodents such as rats, squirrels, flying squirrels, mice, lemmings and voles. Other mammals eaten regularly include shrews, bats, armadillos, muskrats, martens and weasels. Regular bird prey includes woodpeckers, grouse, crows, pigeons, herons, gulls, quail, turkey, passerines, coots, ducks, even raptors up to the size of Red-tailed Hawks and Snowy Owls. In fact, the Great Horned Owl is also a potential predator of every other owl species found in the Americas, of which there are several dozen. Charmingly, bird prey are often plucked before being eaten and the legs and much of the wings are torn off and discarded. Occasional supplemental snacks include reptiles (particularly young American alligators), amphibians, fish, crustaceans, centipedes, scorpions and earthworms. The Great Horned Owl will also prey, if rarely, on domesticated animals, including cats and small or young dogs. (What, no sharks? Color me unimpressed.)
Unsurprisingly, there are almost no predators of adult Great Horned Owl, although they do get themselves killed in confrontations with large eagles, Northern Goshawks, Snowy Owls and, mostly, other Great Horned Owls. However their eggs, nestlings and fledglings are vulnerable to foxes, coyotes and wild or feral cats. Far-ranging as it is, the Great Horned Owl is not presently considered a globally threatened species. Most mortality in modern times is human-related: they can die on impact when they fly into man-made objects such as buildings or cars, and can be electrocuted by contact with power lines.
Like all owls, Great Horned Owls do not build their own nests, usually taking over the nests of other large birds. Old crow and raven, Red-tailed Hawk or large squirrel nests do nicely in North America. However, these birds are not dependent on old nests: they can also use cavities in trees, deserted buildings, and sheltered depressions on rocks. Males select nesting sites and bring the females’ attention to them by flying to them and then stomping on them. Pairs typically breed together year after year and may mate for life. Awww.
- Internet Bird Collection: top rated photographs of birds.