Thrushes have some of the loveliest songs among North American birds.
American Robin singing before dawn (July, ME)
The first two phrases are the typical "caroled" notes, and the next two are higher pitched "hisselly" phrases (see the sonagram). The typical American Robin sings 10-20 different carols and 75-100 different hissellys (Kroodsma). Hissellys are heard most reliably at dawn and dusk. During the day robins usually sing only caroled phrases.
This bird hidden in a conifer sang a song comprised only of hissellies (90 minutes after sunrise, Apr, PA). It was then chased off by a rival male.
Veery, at least two, possibly three birds countersinging, with calls in between song phrases (July, ME).
Hermit Thrush (July, ME)
Hermit Thrushes alternate lower with higher phrases.
The first three phrases:
Two Hermit Thrushes countersinging (July, ME).
Wood Thrush (June, NJ).
Wood Thrush singing a song variant with calls and short phrases (with Carolina Chickadee, June, NJ)
Swainson's Thrush (June, AK)
Swainson's Thrush singing an abbreviated song (June, AK)
Gray-cheeked Thrush (June, AK)
Eastern Bluebird (Oct, PA).