Listening to a Continent Sing

I'm going to let this robin have his say, over a full quarter hour:

How much less interesting birdsong would be without the American robin to provide some intrigue! This bird begins in typical fashion here, singing a string of low carols followed by a soft, high hisselly note. It's not always easy to tell which is the ending hisselly phrase and which is still a carol, partly because he sometimes mutes the carol, making it sound more like a hisselly. But don't worry about the details--just feel the overall rhythm.

Before long, there are more and more hisselly phrases. I'm fascinated, and you hear my footsteps as I walk closer to him. Then he seems to moderate some, singing few hisselly phrases, but then the hisselly phrases surge again. And he's on a tear, with none of the standard pause that one expects after a hisselly and before the next carol. Soon it seems he's singing all hisselly notes, together with a high, thin note that's typically thought of as the "hawk alarm" (first heard at 4:55). He introduces some of the other calls in his vocabulary, too (e.g., 6:14, 6:18), so that the low caroled phrases have all but disappeared from his performance.

Finally, at 9:29, he flies from the oak to the pine tree across the parking lot, and then he unleashes a string of 17 carols in nine seconds, followed by a single hisselly! What gives now?

Then a rather odd thing happens. Normally, he would deliver his carols and hissellys with considerable variety, and one never knows what's coming next, but he's anything but normal here. For ten seconds, from 9:57.5 to 10:07.5, he's stuck on three different carols (A, B, C) and a single hisselly (1), so that his singing sequence here is 1 A 1 B A 1 A 1 A C B 1 A B B 1 C 1 A 1 C 1 B. That's 23 phrases in 10 seconds, more than one every half second, at a clip of 138 phrases per minute. What's got into him?

He continues on through this 15 minute selection, varying his performance in the most unpredictable ways, "singing" his calls and alarms and hissellys and carols, muting them at times, and delivering them in combinations that, to him no doubt, the situation calls for.

And just what might that situation be? What's going through his head for him to express himself in this fashion? There was a scarlet tanager nearby, but I don't think that he'd obsess about the tanager. It must have been another robin, and I thought I caught a glimpse of one, but could never quite be sure. It was back there at 9:29 when the robin flew to the pine that I thought I saw the other one, perhaps a competitor up there in the pine, and that was when the string of low carols was unleashed. Let there be no doubt: I love robins!

Background

Scarlet tanager, tufted titmouse, ovenbird, pileated woodpecker, chipping sparrow, eastern wood-pewee, blue-gray gnatcatcher, red-eyed vireo. Several times (e.g., 6:38, 8:14, 9:15) a "hoarse robin" scarlet tanager sings--don't confuse his burry songs with that of the robin. A tufted titmouse calls loudly at 11:47, then sings a little later.

Photo by John Van de Graaff