Thursday, March 10, 2011

Answer: Can birds sing more than one note at a time?

The short, somewhat surprising answer is YES!

There are many ways to solve this particular challenge.  Here's how I figured it out.

My first query:  [ bird song two notes at once ] leads to a number of books and articles, many with tantalizing hints.  I quickly learned that I had to tell the difference between simultaneous notes and rapid alternation between notes.  Question is, how would I do this differently in my search?

The first hit for this query was the Wikipedia article on Bird vocalization.  Reading through that I learned that the syrinx is sound-producing organ in birds AND that there are two sides to the syrinx, both of which can be controlled independently.

An Image search for [ synrinx ] quickly shows a lovely diagram at

On the left is the external view, on the right is the cross-section.  Unlike the human trachea, the two sides can be both used simultaneously to produce two notes at once.

This led me to do the query: [ synrinx two notes ] for which the first hit is the Wikipedia entry Lateralization of bird songs.  A fascinating story, the article points out how birds can use both synrixes to create different pitches by switching back and forth between the left and right syrnix (for example, the left creates a high-pitched tone, while the right produces a low-pitched tone).

Or, they can switch back and forth very rapidly to create complex and rapid songs.

But what about two notes at the same time?

While reading the article, I found the link to the Wikipedia article on bird song which points out that several species CAN produce two tones at the same time!

This discussion led me to do another query:  [ bird syrinx two notes at once ] which led me to the outstanding discussion at on bird song polyphony.  (Why did I do [ bird syrinx...] ?  Answer: to discriminate between "syrinx" as a performance piece for solo flute and the anatomy of birds!

This article in EarBirding explains the multiple ways a bird can create two (or more!) notes at once, through regular polyphony, overtone, heterodyne and sidebar acoustics.  (Read their page for a great example of the details!)

And, as regular reader Hans points out,  you can see how it works in this fantastic flash animation of syrinx bivocality.  (from:

Interestingly, humans can sing more than one time at a time as well.  We just can't use a syrinx to do it!   See "overtone singing," or listen to it here.



  1. my favorite are "huun huur tur" and "tenores the orosei", if you like overtone singing they rule :)

  2. – Tuvan polyvocal throat singing by the group “Huun huur tur”
    RRR has a good point. Check out: – for an example of the Sardinian *Cantu √° Tenores* polyvocal traditional singing as sung by the group “Tenores De Orosei.” Another group that performs this style of music is “Tenores di Bitti”