The term 'Harbinger of Spring' is often used to describe the signs of the season's arrival. The crossword solutions for this term are ROBIN (5 letters), BUD (3 letters), THAW (4 letters), Tulip (5 letters), and RedRobin (8 letters). The ROBIN is a small, migratory bird that is often seen in the springtime, and its bright red breast is a sign of the season's arrival. The BUD is a sign of new growth, as it is the first stage of a flower or tree's development. The THAW is the melting of snow and ice, which signals the end of winter. The Tulip is a brightly colored flower that is often associated with the spring season. Finally, RedRobin is a restaurant chain that is known for its seasonal menu items, such as its strawberry lemonade, which is a popular drink in the springtime.