The term 'Migratory Songbird' refers to two species of birds, the BOBOLINK (8 letters) and the Vireo (5 letters). The BOBOLINK is a small black and white bird that breeds in North America and migrates to South America in the winter. It is known for its melodious song. The Vireo is a small passerine bird found in North and South America. It is known for its distinctive vocalizations, which are often used to mark territory. Both species are important to the ecosystem, as they help to control insect populations.