|The Hermit thrush (source)|
A harmonious blend of math, science, music and nature came together this week in a study on the songs of Hermit thrushes published by the Proceedings of the National Academy of Sciences. Thrushes have long been favorites of birders for their musical songs. Researchers have now found that the Hermit thrush prefers to sing songs in harmonic series. This is a musical preference that humans share with the birds. A harmonic series is a music and mathematics concept where a musical series begins at a base note and continues with a frequency in multiples of that note. For example: a series of notes begins with a frequency of 1,000 Hz, proceeds to 2,000 Hz, 3,000 Hz, and so on.
The question of whether bird songs follow the patterns of human music has been an interesting research topic that has yielded mixed results. Although we cannot prove that birds are basing the structure of their songs on scales, it seems that this thrush has a preference to do so. The hermit thrush is not limited to the notes it sings by any physiological constraint of its vocal chords, it is indeed choosing the notes it sings from its vocal repertoire. They could be choosing to sing this way because they find it pleasing to the ear, as we do, or it could simply be because harmonic scales are easier to remember, as they are for us. We have often toyed with the question of whether human music is a construct of biology or culture. Perhaps this is an indication that there is more biology at work than we realize.
Studying bird songs can be a fascinating way to identify birds and enjoy nature. Cornell's Lab of Ornithology is a treasure trove of information, educational materials and fun activities for the science classroom or the casual birder. A new tool available from Cornell is "Bird Song Hero". Bird Song Hero is a bird song matching game that allows you to hear and visualize the songs of various birds. Playing it is a great way to hone your bird identification skills.
This is an excellent opportunity to meet several learning styles, auditory and visual in the science classroom. The tutorial shows you how to "read" the visual spectrogram of a bird song and match it to what you are hearing. Maybe a mnemonic device is more your style? Fernbank Science Center in Atlanta, Georgia has put together an extensive list of bird song mnemonics. You may already be familiar with some of these, for example: "Who cooks for you? Who cooks for you all?" (Barred Owl), "Cheerily, Cheer up, Cheerily" (Robin). Try Bird Song Hero or these mnemonics to determine which method is best for you to remember, identify and appreciate your bird songs. We might have more in common with our feathered friends than we realize!
Proceedings of the National Academy of Sciences "Overtone-based pitch selection in hermit thrush song: Unexpected convergence with scale construction in human music"
Bird Song Resources and Activities: