Kiwi or rhea

• The kiwi is the smallest one
• Kiwis
• Ostrich or emu
• Flightless birds having flat breastbones lacking a keel for attachment of flight muscles ostriches
• Rhea or cassowary
• Emu or kiwi
• The emu, for one

WordNet Word definitions in WordNet
n. flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds [syn: ratite bird , flightless bird ] [ant: carinate ]

Wikipedia Word definitions in Wikipedia
A ratite is any of a diverse group of large, flightless birds of the infraclass Palaeognathae . The systematics involved have been in flux. Some sources state that ratites include all the flightless birds of the Palaeognathae; previously, all these birds ...