Synonyms for Snowbird (same or very similar meaning)
WordNet sense 1 (medium-sized Eurasian thrush seen chiefly in winter):
fieldfare, Turdus pilarisWordNet sense 2 (white arctic bunting):
snowflake, snow bunting, Plectrophenax nivalisWordNet sense 3 (small North American finch seen chiefly in winter):
juncoFrom the ODE community, based on WordNetadd/edit