Spring, in its various stages, is ushered in by different events, usually the return of certain birds or the blooming of different flowers. The cardinal, however, is not a migrant. He originated in the warm South where migration was not necessary. As he extended his range to the north, lacking the instinct to go south, he coped with winter instead of avoiding it. He indicates spring not with his arrival, but with his song. Anyone who can whistle can imitate the cheerful "tweet, tweet, tweet" or "teer, teer, teer". There are different accents for different occasions and locations but the feeling is that of happy brightness.
The serviceberry or shadbush is, to me, the first flowering tree of spring. Long before other buds are bursting and even before the full development of its own leaves, this little tree illuminates the gray edges of wood lots with its white blossoms.