They found that when birds evolve from a flying ancestor to a new flightless form, the birds' bodies, including the ratio of their wings and tails, change before the feathers do.

Add in the fact that cassowaries are some of the most territorial birds on the planet, and there’s no confusion about how they earned their title of the world’s most aggressive bird.

More than 99% of birds can fly. But that still leaves many species that evolved to be flightless, including penguins, ostriches, and kiwi birds. In a new study in the journal Evolution ...

No, birds are not mammals. Rather, they are avians. Mammals are characterized by their milk glands, hair, vertebrae and their birthing of live young (being viviparous), according to Britannica ...

7 fascinating flightless birds When we think of birds, flying is usually the first thing that comes to mind– wings spread wide, gliding through the sky.

Kakapos are large, flightless parrots native to New Zealand. These birds can’t fly because they have short wings and lack a keel on their breastbone, where other birds have their flight muscles.

Meet The Kagu: Rare, Flightless, And With An Unusual Feature Seen In No Other Bird This fun-looking forest-dweller spends plenty of time with its beak in the ground.

Researchers have found New Zealand's endangered flightless birds are seeking refuge in the locations where six species of moa last lived before going extinct.

What new research on the avian brain and REM sleep in birds might reveal about our own dream lives.

No other animal is as inexorably linked with extinction as the dodo, an odd-looking flightless bird that lived on the island of Mauritius in the Indian Ocean until the late 17th century.

Study in Evolution journal compares flightless bird evolution, revealing how feathers and bodies change when birds lose flight ability.