Pitch refers to how high or low a sound is on the musical scale, and inflection is change in pitch. This page will introduce you to five basic types of inflection (monotone, upslur, downslur, overslur, and underslur) in both single notes and series.
Listen to this song of the Black-capped Chickadee, which consists of three monotone whistles. You can tell they are monotone (unchanging in pitch) because they are straight horizontal lines on the spectrogram.[audio:http://earbirding.com/blog/wp-content/uploads/2009/06/bccss1str-ndp2008-22-07fade.mp3]
You should be able to see and hear that the first note of the chickadee’s song is higher than the others, while the other two are lower, on the same pitch. There is a change in pitch between the first and second notes, but there is no change in pitch within any of the notes. That’s why we call them monotone.
Extra credit: Note the rhythm of this song. The break between the first and second notes is much longer than the break between the second and third notes. In fact, the second break is so brief that some people may not notice it, especially in the field. Those who hear two notes usually transcribe this song as fee-bee. Those who hear three may transcribe it as hey-sweetie.
Extra extra credit: See the faint copy of the sound above the original? That’s the first harmonic. If you look carefully you’ll see that it’s found at precisely twice the frequency of the original sound. You’ll see more harmonics on the spectrograms below. We’ll talk more about them later, but for now you can ignore them, since your ears don’t consider them a separate part of the sound.
An upslurred sound rises in pitch. Upslurs rise on the spectrogram from lower left to upper right, like this Phainopepla call:
A downslurred sound falls in pitch, and also falls on the spectrogram from upper left to lower right, like this Lesser Goldfinch call:
Bird sounds that rise and then fall in pitch are so common that we really need a word to describe them. The word I use is overslur. The call of the Dusky-capped Flycatcher is an overslurred whistle:
The opposite of an overslur is an underslur: a sound that falls and then rises in pitch, like the call of the Eastern Wood-Pewee. (This sound is actually a little more complicated since the spectrogram shows a small initial upslur, but it’s brief enough and faint enough that you probably can’t hear it.)[audio:http://earbirding.com/blog/wp-content/uploads/2009/06/eawp1c-ndp2007-32-01.mp3]
Inflection of series vs. inflection of notes
Here’s a slightly more complex sound:[audio:http://earbirding.com/blog/wp-content/uploads/2009/06/canwsdownslur1str.mp3]
This is a downslurred series of downslurred whistles. We say the series is downslurred because each note in the series is slightly lower-pitched than the last. We say each note is downslurred because it descends in pitch from start to finish.
Canyon Wrens always sing a downslurred series, but the inflection of each note is variable. Here’s the same individual Canyon Wren singing another of its songtypes, this one a downslurred series of upslurred whistles:
Extra credit: Note that in the above songtype, the first few notes are much different than the last few notes: they are higher-pitched, shorter, and simpler. As the song nears its finish, the tone quality changes to be a little bit more musical, because the upslurs are not so steep, and also a little bit more rich or mellow, because the pitch is lower. The serpentine shape of the last few notes causes them to sound somewhat disyllabic.
The series can be monotone as well, even if the individual notes are not. Here’s a monotone series of downslurred whistles given by a hybrid titmouse in Texas:[audio:http://earbirding.com/blog/wp-content/uploads/2009/06/bcxtutis1str-ndp2008-12-41.mp3]
(Next page: Musicality)