Here is a side-by-side comparison of the “bird call” motives I refer to throughout the transcriptions of Clarence Ashley, Hobart Smith, Rufus Kasey, JL Tyree, Dink Roberts, and John Snipes. This motive or A part of the tune comes at the beginning of each version and then repeats at various times during each performance. I call this common thread the “bird call” motive because each variation involves a repeated interval that could be mimicking the actual Cuckoo bird. (For example, the Common Cuckoo’s bird call is characterized by a repeated interval of a minor third from higher note to lower note in a short-long rhythm. See this page for an audio clip of a Common Cuckoo.)
In Ashley’s version, it is seen in the upbeat to each measure where there is an oscillation between D and G. Smith’s and Tyree’s versions are very similar in how they use the D to G interval as the recurrent one. Roberts and Snipes, however, use G and F (between F-natural and F-sharp) to create this oscillation. Rufus Kasey’s version does not include this kind of oscillation, but it quite similar to the others in how it descends from the high G to the low G.
All versions involve this descent from the high G that moves through the notes of the scale to be used in the performance. An interesting difference between Ashley’s and Smith’s versions is how Smith adds in an extra beat in the middle of the measure. Instead of descending G-F-D-C-Bb-G followed by an upbeat leading back to the high G, Smith adds an extra D-C-Bb, thereby creating a measure of five-beat length instead of the more common four beats. This “hiccup” in Smith’s version adds to the intense drive and forward propulsion of the tune. Roberts’ and Snipes’ variations are interesting in how they use F#s and in how they oscillate between the two highest notes before making their descent.