laughing gull vs Larus ridibundus

laughing gull and Larus ridibundus both are nouns.

Word	Noun	Adjective	Verb	Adverb
laughing gull	Yes	No	No	No
Larus ridibundus	Yes	No	No	No

As nouns, laughing gull and Larus ridibundus are synonyms defined as:

Other synonyms of laughing gull include blackcap, pewit, pewit gull.

laughing gull (noun)	Larus ridibundus (noun)
small black-headed European gull	small black-headed European gull