3. American robin songs.
2. Birds and Their Sounds
Birds sing and call
From page 11 in the book.
American robin songs. Discover something about robins that no one else seems to have explored. A robin sings "several" low, caroled phrases in a series before pausing or offering a high, screechy note (a hisselly, though some hear it as eek), but exactly how many carols does he sing? Or how many eeks? Do the numbers change through a singing session, or from early morning to midmorning to midday to afternoon to evening? Or from one week or month to the next? And how about the ratio of carols to eeks? What might you learn about the mind of a robin by simply counting his songs like this? No one yet knows.
You can listen to patterns in robin singing anywhere and everywhere, as suggested above, thereby documenting a general pattern in robin singing for whatever time scale you choose. Even more satisfying, however, might be to learn how an individual robin sings over time. Many robins can be recognized as individuals by a unique carol or two (see "How a Repertoire Is Delivered," p. 94), and you can use those unique carols to ensure that you are listening to the same robin from hour to hour or day to day.