EXPLORING SELECTED BIRD VOCALIZATIONS
Selected Vocalizations Slowed to Reveal Dynamics of Overtones and Harmonics
This section presents an informal, and hopefully interesting, comparison of selected bird vocalizations displayed at different speeds. Real-time vocalizations are matched with the same sounds slowed between 4x to 32x normal speed to reveal the intricacies of overtones and harmonics that pervade most bird voices. Such sound dynamics are especially evident in the Oscines or songsters of the order Passeriformes, although such sound dynamics are also heard in other bird orders as well (e.g., listen to the slowed version of the Red-Tailed Hawk's call, below).
Listen to the remarkable similarities in sound dynamics among species, most apparent in the slowed sounds, despite the great differences we perceive in the normal-speed vocalizations. Among species, note the similarity of calls (e.g., compare American Robin with Red-breasted Sapsucker; and Western Tanager with Winter Wren) and songs (e.g., Bewick's Wren with Yellow-rumped Warbler). The particularly unusual vocalizations of three species presented here -- Red-tailed Hawk, Varied Thrush, and Western Wood-peewee -- also make for an interesting comparison. The Peewee's call has been slowed 32x; listen to the remarkable and changing harmonics in this complex yet brief call.
| Species | Normal speed | Slowed |
| American Robin | call | call slowed 8x |
| Bewick's Wren | song | song slowed 4x |
| Olive-sided Flycatcher | song | song slowed 8x |
| Red-breasted Sapsucker | call | call slowed 4x |
| Red-tailed Hawk | call | call slowed 8x |
| Townsend's Solitaire | song | song slowed 4x |
| Varied Thrush | song | song slowed 8x |
| Warbling Vireo | song | song slowed 8x |
| Western Tanager | call | call slowed 8x |
| Winter Wren | call | call slowed 8x |
| Wrentit | song | song slowed 4x |
| Western Wood-Peewee | call | call slowed 32x |
| Yellow-rumped Warbler, Audubon's race | song | song slowed 8x |
The Diversity of Song Sparrow Songs
One of the more diverse songsters of the Douglas-fir forests, particularly of the riparian habitats therein, is the Song Sparrow. Whereas other species such as the Hutton's Vireo might have a greater variety of different sounds, the Song Sparrow excels in the great number of variations on a single song theme.
Following are 12 examples of selected Song Sparrow songs, taped by Bruce Marcot in inland Humboldt County, northwestern California, Douglas-fir forest. All songs were sung by a single individual male Song Sparrow over a period of 2-3 hours. Each song differs in its cadence, phrases (single notes, trills), or sequence of phrases. See if you can identify separate phrases that sometimes appear in new sequences.
SONG SPECTROGRAM Song 3 Song 4 Song 12
