Answer:

dodo

Answer	Crossword Clue
DODO	Extinct bird
DODO	Once a bird
DODO	Dunderhead

DODO	Dumb cluck
DODO	This was a bird
DODO	Ninny
DODO	Dummy
DODO	Blockhead
DODO	Lamebrain
DODO	Dull-witted one
DODO	Extinct Mauritian

DODO	Bygone bird
DODO	Birdbrain
DODO	Extinct flightless bird
DODO	Former forest dweller of Mauritius
DODO	Bird on the Mauritian coat of arms
DODO	Flightless bird of old
DODO	Doofus
DODO	Wonderland bird

DODO	Bird extinct since the late 17th century
DODO	Clumsy extinct bird
DODO	Numskull
DODO	Extinct bird, or birdbrain
DODO	Dimwit
DODO	Ding-a-ling
DODO	Knucklehead
DODO	Birdbrain, or extinct bird

DODO	Extinct pigeon relative
DODO	Ignoramus
DODO	Exemplar of extinction
DODO	Fogy or dullard
DODO	Thickheaded one
DODO	Bird related to the pigeon
DODO	Bird clubbed to extinction
DODO	Jerk

DODO	Long-extinct bird
DODO	Numbskull
DODO	Boob
DODO	Old fogy
DODO	Not-so-sharp bird