Bird

Birds encompass such an enormous variety of species that common traits run thin among them. Their bodies are all or mostly feathered, though a few such as vultures lack feathers on their heads. Their feathers may be brightly coloured, such as in hummingbirds, parrots, and canaries, or dull and muted, such as in sparrows and female mallards.
  These feathers can be smooth and sleek as in penguins, have a shaggy appearance as in ostriches and cassowaries, or be large and flamboyant such as in male peacocks.
  They mostly have beaks, but waterfowl have broader bills instead. Beaks can be long and needle-like as in the hummingbird, incredibly strong as in woodpeckers and nuthatches.
  The feet are generally featherless and end in four toes with one back-facing. Predatory species often feature talons, sometimes of fearsome size, as with eagles, falcons, vultures, and hawks. Leg length ranges from the absurdly lanky flamingo to the shuffling emperor penguin.

While all birds have wings, not all are capable of flight. The kiwi, emu, and penguin are some examples of flightless birds. Of those which can fly, the speed and duration of their flight is incredibly varied.
  The Albatross has the longest flight duration, able to fly for days at a time without landing. The arctic tern has the largest migratory range, crossing the entire Endless Sea each year. Owls are the quietest flyers, disturbing only a bare minimum of air in their travel, while hummingbirds have the fastest wing-speed, too fast for the human eye to observe.
  Intelligence is similarly varied. Most have too little to be trainable or bear much purpose for domestication, but there are exceptions. Pigeons can be trained to remember and return to set locations, even over long distances. Parrots and corvids, including crows, ravens, rooks, jackdaws, and magpies, demonstrate intelligence on par with human children, even using tools and solving puzzles. Many can also imitate speech and use it in context.
  Some birds are social, living in flocks, others gather only to mate and raise young. Nests can be held aloft in trees, hidden in underbrush, or in natural hollows of trees or stones.

The beautiful feathers and song of many species make them popular as pets. Many are also drawn to the intelligence and trainability of parrots and corvids, though proper care can be challenging.
  Some train pigeons and other memetic species as messengers, and many hunters train hawks and falcons to take down and retrieve small prey.

Birds are found everywhere except underground, including over the Endless Sea (gulls, albatrosses, ducks, kingfishers). Peregrine falcons are known to nest on sheer cliffsides, emus and ostriches roam the plains on foot while their flighted cousins swoop from above.
  Wilderness forests are alive with choirs of songbirds, farmers put up scarecrows to keep them from eating seed crops, and city folk complain about pigeon mess in the streets.