Grounded birds are a group of flightless birds that are unable to take off from the ground. This group includes emus, rheas, and DODOS. Emus are large, flightless birds native to Australia that can reach up to 6.2 feet in height. Rheas are large, flightless birds native to South America that can reach up to 4.9 feet in height. DODOS were large, flightless birds native to the island of Mauritius that went extinct in the 17th century.