Program Content

Generally, larger birds have lower voices because their whole vocal apparatus is larger: longer and wider. But there are exceptions to this rule.

Here we use the example of the western screech owl. Although the female screen owl is larger than the male, her syrinx is smaller and her trachea (windpipe) is narrower. So, the male has a deeper hoot.

Sound Sources

Chris Tenney recorded the house finch near Salinas. The recording of the American robin is from CD accompanying the Cornell Lab of Ornithology's Handbook of Bird Biology. The western screech owl duet is from the CDs accompanying the book Nature's Music: The Science of Birdsong.