Sweetwater River, Split Rock, near Jeffrey City, Wyoming
June 11, 7:09 a.m.
Sunrise at 5:33 a.m.
When a rock wren sings, I tend to hear him out, and sometimes that takes hours; here it's only 17 minutes.
I am nestled down in the rock outcroppings above the Sweetwater River, with Split Rock in clear view just downstream. The wind howls through here, and this stretch of the TransAm bicycle trail is well-known as one of the windiest on the entire route.
This rock wren perches above me on the rocks, with an even better view of the landscape than I have; sometimes he's in clear view as he sings above me, but sometimes he drops down so he's just out of sight, his position making quite a difference in how loudly we hear his songs.
And how I love listening to a rock wren motor through his song repertoire of 100 or more songs. I know his style, and can hear it as I listen. Even more fun is to listen again and watch the sonagrams dance by on the computer's monitor as I listen back home, because then I can accurately chart out his progress through his repertoire. In the first minute alone, he sings A B A C B C B D C B D E, five different songs. Very nice. No immediate repeats, with one or two songs of other types between successive renditions of the same type.
On occasion, however, when he seems less enthused about singing, successive songs can be the same. You can hear such repeats beginning at 2:02 (2 songs), 7:12 (4 songs), 11:00 (3 songs), 11:35 (2 songs), and at 12:00 (2 songs).
He'll gradually cycle through his repertoire, eventually returning to these songs tens of minutes later. Given that I have 17 minutes here, I search for song D later in this recording, because D is somewhat unique with its lower frequency and slower rate of repetition and will therefore be more easily found later. I start at the end of the recording and work backwards, and there it is, at 16:56, 16:44, and 16:24, but not again until I return to the first minute, where it occurs at 0:52 and 0:36. If this male sings five different songs every minute, by 16:00 he would have delivered about 80 different songs before he started to repeat some of his earlier songs. A thorough study of this male, with an hour's worth of his singing, could reveal a song repertoire size of well over 100 different songs.
Wind! Canada goose (5:12), occasional muffled sounds of a few other birds, such as a willet (16:17).
Photo by Brian L. Sullivan
Photo by John Van de Graaff