One of five different header images loads at random each time you visit a page on this blog; each shows a bird in its natural habitat, overlaid with a spectrogram of one of that species’ sounds.
The Bobolink song in this header was recorded in Larimer County, Colorado on 5/31/2007:
No other North American bird can match the “video-game soundtrack” quality of the Bobolink, which it often sings in a flight display over lush meadows and tallgrass prairies. The rendition above switches rapidly and repeatedly from whistled to nasal to burry to polyphonic tone qualities. Multiple short motifs are repeated; see if you can find the repeated sections, either by looking at the spectrogram or listening to the audio.
Hermit Thrush song recorded in Larimer County, Colorado, 6/11/2007:
Ethereal and melancholy, this is the quintessential sound of a summer evening in the Rocky Mountains. The long, clear introductory whistle in each strophe gives way to a terminal polyphonic flourish of great intricacy and variety. Claude Debussy said “music is the space between the notes,” and the Hermit Thrush knows it, letting plenty of silence well up between strophes.
Prairie Falcon courtship screams recorded in Jefferson County, Colorado, 4/1/2010.
There are few wilder sounds than the screams of courting falcons, and this spectrogram shows why: like all large screeching birds, they mix the nasal with the noisy, and their voices occasionally break to a higher register. I love the combination of shading and parallel lines, some with lockstep squiggles, set here against the backdrop of the falcon’s canyon habitat.
Ruby-crowned Kinglet song recorded in Larimer County, Colorado, 6/1/2008.
Nothing beats this spectrogram for calligraphic intricacy. The three sections of the kinglet’s song are as distinct to the eye as they are to the ear, and the wonderful conglomeration of faint, sharp harmonics in the middle part is particularly marvelous.
Western Meadowlark complex song (or “flight song”) recorded in Pueblo County, Colorado, 5/13/2011.
The typical song of meadowlarks, lovely though it is, seems brief and uninspired compared to their flight songs, in which they pull out their polyphony and sing in fast forward. If you’ve forgotten that meadowlarks are related to Bobolinks, the flight songs will remind you. The similarity of the spectrograms is a family resemblance. Like most renditions of the flight song, this one is introduced by a well-spaced series of clear, downslurred whistles. If you hear a series of such whistles from a Western Meadowlark in the field, the bird may be giving you fair warning that a flight song is about to start.