Changes

The smallest bird - and arguably one of the smallest terrestrial vertebrates alive - is the bee hummingbird (''Mellisuga helenae''), about 2.4 inches long and weighs 0.092 ounces.  The largest was an extinct species of [[elephant bird]] (''Vorombe titan'') of Madagascar, which stood 9.8 feet tall and weighed nearly a ton.  Currently, the largest living bird is the [[ostrich]] (''Struthio camelus''), standing up to 9 feet tall, and weighing up to 320 pounds.

The smallest bird - and arguably one of the smallest terrestrial vertebrates alive - is the bee hummingbird (''Mellisuga helenae''), about 2.4 inches long and weighs 0.092 ounces.  The largest was an extinct species of [[elephant bird]] (''Vorombe titan'') of Madagascar, which stood 9.8 feet tall and weighed nearly a ton.  Currently, the largest living bird is the [[ostrich]] (''Struthio camelus''), standing up to 9 feet tall, and weighing up to 320 pounds.

All the birds, except the [[moa]]s and elephant birds, have the two front limbs modified in wings and this characteristic allows almost all the species to fly; the feathers on the trailing edges of the wings and tail lengthened, widened, and stiff, enabling birds to not just engage in flight but to be masters at it.  Birds' feathers can be any color, and the colors and pattern often vary between males and females of the same species, with males typically having the more garish and elaborate plumage; in many species such as [[peacock]]s and [[birds of paradise]] this is taken to striking extremes.

All the birds, except the [[moa]]s and elephant birds, have the two front limbs modified in wings and this characteristic allows almost all the species to fly; the feathers on the trailing edges of the wings and tail lengthened, widened, and stiff, enabling birds to not just engage in flight but to be masters at it.  Birds' feathers can be any color, and the colors and pattern often vary between males and females of the same species, with males typically having the more garish and elaborate plumage; in many species such as peacocks and birds of paradise this is taken to striking extremes.

Most birds are highly intelligent, and species such as crows and parrots are considered to be among the most intelligent of animals. Many birds are in fact able to modify and use small objects to pursue their own purposes, and it is now established that in some species there is a transmission of knowledge between generations. They are sociable animals that often live in colonies, communicating thanks to visual or auditory signals. They often participate in social behaviors such as hunting and defense.

Most birds are highly intelligent, and species such as crows and parrots are considered to be among the most intelligent of animals. Many birds are in fact able to modify and use small objects to pursue their own purposes, and it is now established that in some species there is a transmission of knowledge between generations. They are sociable animals that often live in colonies, communicating thanks to visual or auditory signals. They often participate in social behaviors such as hunting and defense.