pigeon hawk vs merlin

pigeon hawk and merlin both are nouns.

Word	Noun	Adjective	Verb	Adverb
pigeon hawk	Yes	No	No	No
merlin	Yes	No	No	No

As nouns, pigeon hawk and merlin are synonyms defined as:

pigeon hawk and merlin: small falcon of Europe and America having dark plumage with black-barred tail; used in falconry

Other synonyms of pigeon hawk include Falco columbarius.

pigeon hawk (noun)	merlin (noun)
small falcon of Europe and America having dark plumage with black-barred tail; used in falconry	small falcon of Europe and America having dark plumage with black-barred tail; used in falconry