Synonyms for Broadbill (same or very similar meaning)
WordNet sense 1 (diving ducks of North America having a bluish-grey bill):
bluebill, scaup, scaup duckWordNet sense 2 (freshwater duck of the northern hemisphere having a broad flat bill):
shoveler, shoveller, Anas clypeataWordNet sense 3 (tropical American heron related to night herons):
boatbill, boat-billed heron, Cochlearius cochleariusFrom the ODE community, based on WordNetadd/edit