Today's "song" doesn't sound much like a song. I can't even prove it was made by a bird. But it is completely typical of the many recordings of singing with clicks by the Yellow Rail. Those clicks are not musical, but they do have characteristics of a standard bird song. Pause the moving sonogram between 0:04 and 0:05 to see a single song. The ongoing performance is not a willy-nilly string of clicks delivered at random intervals. It is a string of these songs, each with two slow clicks followed by three fast ones. The 1-2 interval and the 2-3 interval are equal, while the 3-4 and 4-5 intervals are shorter and also equal. These songs are repeated in such short order that the entire serenade sounds like he is alternating doublets and triplets, as Pieplow says. You can follow the rhythm through this cut. If he drops part of a song, he waits a bit to resume. To put it differently, when he is interrupted, he resumes at the beginning of a 5-click song.
I can't prove the singing I recorded was made by a bird, because I didn't see it. This was at night, when Yellow Rails typically sing. All rails are hard to see, but Yellow Rails are especially hard to see. I have never seen one. But when I moved to Oregon and learned that an isolated population of this species nests in the Klamath Basin, I became determined to at least hear and record one. Several trips to Ft. Klamath were of no avail. (Attempts to find them elsewhere, e.g., Gerber Reservoir, were also of no avail.) But eventually, on a moonless night, I did have success on Dixon Road north of Fort Klamath. I followed advice and clicked two small rocks together in the cadence of the song to get them going, then I turned on the recorder. I thought the bird was well out in the field so I tried to get closer by walking along the road, but I couldn't get any "closer." Finally I blurted out, "How's he staying ahead of me?" I was scanning the shoulder of the road with the "nightshot" option of my campcorder, but saw nothing. He may have been on the road, keeping a safe distance from the uninteresting mammal while hunting for the competitor who had invaded his territory. I don't know. I keep checking the video for a fleeting glimpse of a Yellow Rail. No cigar. But I like the story.