WordNet records no synonym and no antonym for columbiform bird. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a cosmopolitan order of land birds having small heads and short legs with four unwebbed toes
Synonyms, antonyms and the broader and narrower relations for columbiform bird come from Princeton University’s WordNet. Full sources and licences.