City Creek Nature Notes – Salt Lake City

July 11, 2017

July 6th

Dry Fork Canyon

3:45 p.m. It is the third day of 100 degree Fahrenheit heat as I return to the Bonneville Shoreline Trail behind the University of Utah Hospital. I plan to jog up Dry Fork Canyon at the southeast end of the Salt Lake salient and then west along the Shoreline Trail above the Avenues. The Trails goes up Dry Fork for about one mile, crosses a pass, and then traverses a series of gullies that come down from the ridgeline to the Avenues and city below. The Trail begins in a invasive Cheat grass sea that is typical of the city’s foothills. Here, small light brown House crickets (Acheta domestica), another non-native, infest the Cheat grass. There are twenty or thirty per square yard. I round a corner into Dry Fork Canyon, and quickly its narrow walls close in and shade the canyon. The Fork’s walls are covered in dense Gambel’s oak forest, and this forest broken higher up by fields of the brown sun-dried husks of Arrowleaf balsamroot (Balsamorhiza sagittata). In an example of color adaptation, at the base of the oaks, larger, unidentified grasshoppers live, but unlike the sun-exposed crickets, these are colored green in order to better blend in with their surroundings.

At a seep one-third of a mile up canyon, there is a mini-oasis. In ten feet with Wood’s rose bushes on either side, Common sulphur butterflies, Western tiger swallowtail butterflies, small bluet dragonflies, Common whitetail dragonflies, Western Yellowjacket wasps, and Circumpolar bluets, all compete for space and landing rights around a small ditch of shallow water.

Further up canyon, the oak forest comes alive with sounds of birds: Black-headed grosbeaks, Lazuli buntings and Song sparrows call from the oaks spaced perhaps 100 feet apart on both canyon walls. Their songs are clear and strong, and I estimate there are about 250 birds between the canyon mouth and the upper pass. Unexpectedly, this density exceeds that of the stream areas in City Creek Canyon. The birds here, unlike in the City Creek Canyon, are fearless. I am able to stand only five feet from a Lazuli bunting as it tilts its head back to make a song. I am able to make a good recording and spectral graph. I flush two California quails (Callipepla californica) from the brush.

House crickets may explain the high density of birds in Dry Fork Canyon, where as the name implies, there is no water. Assuming a cricket weighs about one-quarter gram (0.000551 lbs), then there are about 85 tons of cricket mass on the city facing foothills between Dry Fork Canyon and the peak at the top of North Terrace Hills Drive in Valley View Canyon (see June 10th) (3,097,600 square yards per square mile x 4 miles x 1.25 miles x 20 cricket per square yard x 0.000551 lbs. per cricket divided by 2,000 lbs. per ton). The crickets exist at a similar density for another ten square miles between Memory Grove in lower City Creek Canyon and milepost 3.5 above Bonneville Drive. This suggests that there may be about 300 tons of these non-native crickets, and this is more than enough to support the summer bird populations seen in Dry Fork and City Creek Canyon.

As the canyon dries out, purple Bull thistles (Cirsium vulgare) covered with small black ants, a blue-white thin-petaled Eaton’s aster (Aster eatonii a.k.a. Symphyotrichum eatonii), and invasive blue Chicory (Cichorium intybus L.) grow. The roots of Chicory are roasted and ground to make chicory coffee. The white-topped weed Hoary cress (Cardaria draba) is also found.

As I near the upper Trail pass out of Dry Fork, I count two Broad-tailed hummingbirds, and just before the pass, I am treated to a rare display by a pair of Black-chinned hummingbirds (Archilochus alexandri). The male has trapped a female hummingbird at the base of Gambel’s oak sapling. For several minutes the male does its pendulum mating dance. It rapidly flies back and forth in a figure-eight pattern about six feet across, its wings buzzing loudly. Then the male gives up, and he does two high speed runs over the female while making a zinging noise. At the pass out of Dry Fork, I am greeted by expansive views of the city and of the Great Salt Lake, fifteen miles in the distance. The Sun is pounding, but my spirit soars from both the views and the hummingbird’s display.

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Per Thoreau’s “Journal” on July 6th, 1851, he walks by moonlight and again sees it reflected in water. He notes crickets sing with a different frequency at night. On July 6th, 1852, he hears a pewee and a red-eye. He sees tufted vetch, a fern, a tansey, and a parsnip. He watches a pickerel in a stream. He hears a duck on a pond. On July 6th, 1856, he stumbles on a peet-weet with its nest and young. On July 6th, 1858, he hears and sees loons. On July 6th, 1859, he describes heart-leaf.

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On July 6th, 1905, the City passed Councilperson’s Woods proposed ordinance banned automobiles from City Creek Canyon. On the same day, the Salt Lake Tribune urged that the road should be sprinkled with oil to keep dust down. Also on July 6th, 1905, the City Council held a heated debate on whether a bridge should be constructed over City Creek Road in support of the Commercial Club’s proposed scenic boulevard (Salt Lake Tribune).

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