Birds are warm-blooded, feathered and fly (or with flightless birds descend from flying ancestors), lay eggs and care for their young, and have erect stance and a toothless beak.
(Birds; are; warm-blooded, feathered and fly (or with flightless birds) (lay eggs; care; for their young) (Birds; fly; )
Birds lay eggs Birds
are care fly
warm-blooded, feathered and fly (or with flightless birds
for their young