Word of the Day
Clue of the Month
relating to, or characteristic of birds
related; For the birds?; Birdlike; Like a roc; Birdy; Pertaining
once a year
in English language:
44565 / 86800
the Bird Folks: Crows: well behaved and well mannered!
in Motion – Avian Commotion
(class Aves) are bipedal, endothermic (warm-blooded), vertebrate
animals that lay eggs. There are around 10,000 living species,
making them the most diverse tetrapod vertebrates. They inhabit
ecosystems across the globe, from the Arctic to the Antarctic.
Birds range in size from the 5 cm (2 in) Bee Hummingbird to the
2.7 m (9 ft) Ostrich. The fossil record indicates that birds
evolved from theropod dinosaurs during the Jurassic period,
around 150–200 Ma (million years ago), and the earliest
known bird is the Late Jurassic Archaeopteryx, c 155–150
Ma. Most paleontologists regard birds as the only clade of
dinosaurs that survived the Cretaceous–Tertiary extinction
event approximately 65.5 Ma.
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
birds have forelimbs modified as wings and most can fly, with
some exceptions including ratites, penguins, and a number of
diverse endemic island species. Birds also have unique digestive
and respiratory systems that are highly adapted for flight. 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.
species undertake long distance annual migrations, and many more
perform shorter irregular movements. Birds are social; they
communicate using visual signals and through calls and songs, and
participate in social behaviors including cooperative breeding
and hunting, flocking, and mobbing of predators. The vast
majority of bird species are socially monogamous, usually for one
breeding season at a time, sometimes for years, but rarely for
life. Other species have breeding systems that are polygynous
("many females") or, rarely, polyandrous ("many
males"). Eggs are usually laid in a nest and incubated by
the parents. Most birds have an extended period of parental care
species are of economic importance, mostly as sources of food
acquired through hunting or farming. Some species, particularly
songbirds and parrots, are popular as pets. Other uses include
the harvesting of guano (droppings) for use as a fertiliser.
Birds figure prominently in all aspects of human culture from
religion to poetry to popular music. About 120–130 species
have become extinct as a result of human activity since the 17th
century, and hundreds more before then. Currently about 1,200
species of birds are threatened with extinction by human
activities, though efforts are underway to protect them.
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