redheaded woodpecker vs pecker

redheaded woodpecker and pecker both are nouns.

Word	Noun	Adjective	Verb	Adverb
redheaded woodpecker	Yes	No	No	No
pecker	Yes	No	No	No

As nouns, pecker is a hypernym of redheaded woodpecker; that is, pecker is a word with a broader meaning than redheaded woodpecker:

redheaded woodpecker: black-and-white North American woodpecker having a red head and neck
pecker: bird with strong claws and a stiff tail adapted for climbing and a hard chisel-like bill for boring into wood for insects

Other hypernyms of redheaded woodpecker include peckerwood, woodpecker.

redheaded woodpecker (noun)	pecker (noun)
black-and-white North American woodpecker having a red head and neck	bird with strong claws and a stiff tail adapted for climbing and a hard chisel-like bill for boring into wood for insects
	horny projecting mouth of a bird
	obscene terms for penis