jaeger vs arctic skua

jaeger and arctic skua both are nouns.

Word	Noun	Adjective	Verb	Adverb
jaeger	Yes	No	No	No
arctic skua	Yes	No	No	No

As nouns, arctic skua is a hyponym of jaeger; that is, arctic skua is a word with a more specific, narrower meaning than jaeger:

jaeger: rapacious seabird that pursues weaker birds to make them drop their prey
arctic skua: a variety of jaeger

Other hyponyms of jaeger include parasitic jaeger, Stercorarius parasiticus, bonxie, skua.

jaeger (noun)	arctic skua (noun)
rapacious seabird that pursues weaker birds to make them drop their prey	a variety of jaeger