skink vs western skink

skink and western skink both are nouns.

Word	Noun	Adjective	Verb	Adverb
skink	Yes	No	No	No
western skink	Yes	No	No	No

As nouns, western skink is a hyponym of skink; that is, western skink is a word with a more specific, narrower meaning than skink:

skink: alert agile lizard with reduced limbs and an elongated body covered with shiny scales; more dependent on moisture than most lizards; found in tropical regions worldwide
western skink: found in western North American grasslands and open woodlands

Other hyponyms of skink include Eumeces skiltonianus, Eumeces callicephalus, mountain skink.

skink (noun)	western skink (noun)
alert agile lizard with reduced limbs and an elongated body covered with shiny scales; more dependent on moisture than most lizards; found in tropical regions worldwide	found in western North American grasslands and open woodlands