Birds (Aves)

What is a bird? Interesting facts:

The class of birds (lat. Aves) currently contains about 11,000 species. An essential feature of all bird species is the wing pair, which allows the birds to fly. By far not all birds can fly. For example, the ostrich has lost its ability to fly, in favor of its tremendous pace on the ground. The penguin, too, belongs to the class of birds, but now adapted to an aquatic environment in which the ability to fly is no longer necessary.
Some bird species are considered extremely intelligent. Especially ravens and crows are able to solve relatively complex problems. Even tool use has been observed in some species, with e.g. Parrots are far ahead of many mammals in terms of intelligence. By the way: All birds are direct descendants of the dinosaurs. The Archeopteryx is considered as an intermediate form (bridgehead) between reptile and bird.
Birds can be divided into nest stools and nest flies. The nest stools remain after hatching in the nest, as they are usually featherless and blind. In contrast, nest-fliers are already feathered after hatching and thus buoyant.

Characteristics of the birds:

Below is a brief listing of the key features for birds. However, not every bird necessarily has to combine all bird characteristics. For example, e.g. Flying is not a necessary criterion to be regarded biologically as a bird. A good example are penguins and ostriches: these have developed wings, or are too heavy, as still flight ability existed.
pectorals: Birds have huge pectoral muscles in proportion to their height. This ensures their flying ability.
Bürzeldrüse: Many species of birds take care of their plumage with the secretion from the pancreas. Located on top of the tail root, the skin gland releases a greasy substance that 'maintains' the bird's feathers. This guarantees the flying ability.
feathersInstead of fur, as in mammals, birds have feathers. These consist of keratin, the same ingredient that makes up human hair.
wing: The front extremities of the birds are transformed into wings.
flyingAlmost all birds can fly. The few species that can no longer do so come from airworthy species.
Heartbeat: The heartbeat of birds is comparatively high (to that of mammals). As a result, the bird does not need too much blood, making it lighter overall.
hollow bones: Bird bones are hollow. This also keeps the weight of the bird at a low level and guarantees the ability to fly.
cesspool: Ureter and anus form a common body exit.
air bags: In addition to the lungs, birds have multiple air sacs that push the air through the lungs.
magnetic sense: Most birds can perceive the Earth's magnetic field. Birds can reliably reach their destination with this 'inner compass', for example to find a winter home.
beak: All bird species have a beak without teeth.
vertebrates: Belonging to the vertebrates, without exception, each bird has a spine.

List of birds:

Eagle, Albatross, Blackbird, Capercaillie, Oystercatcher, Wagtail, Bluetit, Coot, Bee-eater, Chaffinch, Great spotted woodpecker, Buzzard, Dodo, Jackdaw, Bullfinch, Thrush, Eurasian jay, Kingfisher, Magpie, Emu, Duck, Owl, Hawk, Pheasant, Flamingo, Yellowhammer, Gray Heron, Greenfinch, Green Woodpecker, Hawk, Halibut, Harpy, Great Crested Grebe, House Sparrow, Emperor Penguin, Cockatoo, Kakapo, Canary, Lapwing, Kiwi, Nuthatch, Great Tit, Hummingbird, Condor, Cormorant, Crow, Crane, Cuckoo, Black-headed Gull, Lark, Common Swift, Crinoid, Nightingale, Nandu, Red-backed Shrike, Cockatiel, Blackcap, Seagull, Parrot, Pelican, Guinea Fowl, Peacock, Peachhead, Penguin, Golden-faced, Raven, Barn Swallow, Partridge, Heron, Robin, Red Kite, Barn Owl, Snowy Owl, Rook, Swallow, swan, black kite, black stork, white-tailed eagle, songbird, sparrow, star, golden eagle, little owl, goldfinch, mallard, stork, ostrich, pigeon, turkey, toucan, kestrel, eagle owl, quail, tawny owl, long-eared owl, wandering fawn lark, bald eagle, white stork, budgerigar, hoopoe, wren, zebra finch, zilpzalp