cuckoo vs cuculiform bird

cuckoo and cuculiform bird both are nouns.

Word	Noun	Adjective	Verb	Adverb
cuckoo	Yes	No	Yes	No
cuculiform bird	Yes	No	No	No

As nouns, cuculiform bird is a hypernym of cuckoo; that is, cuculiform bird is a word with a broader meaning than cuckoo:

cuckoo: any of numerous European and North American birds having pointed wings and a long tail
cuculiform bird: birds having zygodactyl feet (except for the touracos)

cuckoo (noun)	cuculiform bird (noun)
any of numerous European and North American birds having pointed wings and a long tail	birds having zygodactyl feet (except for the touracos)
a man who is a stupid incompetent fool

cuckoo (verb)	cuculiform bird (verb)
repeat monotonously, like a cuckoo repeats his call