Dawn Chorus is is track number 19 on Geogaddi. As well as birdsong at daybreak, the title also may refer to the unexplained phenomena known as electromagnetic dawn chorus which occurs during or just after sunrise, effecting radio equipment with a transmission similar to birds' dawn chorus.
Aside from the bird-song variety that all are familiar with, there is an electromagnetic phenomenon of the same name, which occurs when the sun breaks over the horizon during a period of sunspot activity or of solar flares. At such times, those with the proper equipment can hear sounds that have been described as being like whistling, or like hundreds of birds singing at once; some have even reported hearing human voices. [anon]
You might like to read the description of the effect at Wikipedia. That article also has links to WAV files of the Dawn Chorus from NASA's site.
[J] pointed out something interesting: BoC have remixed Meat Beat Manifesto, and the MBM album "Actual Sounds and Voices" contains a very Geogaddi-sounding track called "The Tweek" (track 6). He pointed out that the beginning of the track sounds rather like the beginning of A:B::B:C, and that "a little way through the track, a conversation starts. The two men are discussing radio disturbances/anomalies", and that these are illustrated with pertinent audio samples. "At the end, there is a pause and they begin to play an extended sample of a dawn chorus" that sounds rather like chirping tree-frogs in the summer. One of the men then comments: "The dawn chorus on the other hand is not at all well understood, and there is no theory to explain it." (Actual dawn chorus samples can be heard by following the Wikipedia link given above.)
"It's a mixture of live performance and step sequencing. Sometimes, we make up sounds and then program them tightly in a really synthetic way. Other times, we want it to sound really rough, so we'll just jam on the drums live. For instance, "Dawn Chorus" is a single-take jammed beat that I played, while "1969" has a live beat all the way through mixed with other beat tracks."
The title is a transliteration of David Koresh: Da-wi-dn Core-us.