That's the wise thrush; he sings each song twice over,
Lest you should think he never could recapture
The first fine careless rapture!
Robert Browning

This poem helped me sort out which was which when I first started birding.

AND THE LARKS SHRILL PIPE SHALL COME IN THE MORNING FROM THE FALLOW AND THE BITTERN BEAT HIS DRUM IN THE EVENING FROM THE HOLLOW SIR WALTER SCOTT NICE AND SIMPLE