Listening to a Continent Sing

With metronomic regularity, this sora calls its name, sor-AH, sor-AH, sor-AH. Curious, I measure the calling rate at six places throughout the six minute recording, and obtain values that range from 40 to 43 calls per minute. He is both persistent and consistent, perhaps because he's unpaired and seeking a mate.

Background

American robin, Wilson's snipe, red-winged blackbird (notice how the sora pauses at 0:19 when the blackbird sings), quacking duck, savannah sparrow, killdeer, and the bubbling and gurgling of the Firehole River that drains the Upper Geyser Basin.

Photo by John Van de Graaff