City Creek Nature Notes – Salt Lake City

June 25, 2017

June 25th

Fishing spiders

5:00 p.m. The first mile of road has turned into a green tube, and the garland of butterflies described on June 15th and June 22nd continues. The sky is clear and the air calm. Trees overhang above and views of the stream are obscured by thick underbrush except at picnic sites. The stream can also be accessed at small breaks made by anglers or at small natural breaks. There about ten of these breaks along the first road mile. I force myself through several of the breaks and look down to enjoy the cool, transparent stream. At each I find various types of spider webs: disordered tangle webs, sheet webs hung low just above the waterline, and the circular webs of Orb weaver spiders (Araneus sp.). Paradoxically, I see no spiders today, but their webs are full of hapless arthropod victims.

Lining the stream banks at these breaks are Bittersweet nightshade plants (Solanum dulcamara) a.k.a. Climbing nightshade with deep blue blossoms. These plants hug the stream’s steep banks and vertical rock retention walls, and they grow just above the waterline. At a few places along the first road mile, they incongruously protrude from the understory of serviceberry bushes (Amelanchier sp.), and there they are noticeable because their colorful blossoms are one of the few flowering plants that are left after the spring flower explosion. The Nightshade’s blossoms are either shriveling or extend vibrant yellow cones surrounded by blue petals. In the fall, these will yield bright red fruit.

Looking up from the stream and into the thick green sub-story, there are butterflies everywhere. They are the usual suspects for a canyon spring and early summer: Cabbage white butterflies, Western tiger swallowtails, Mourning cloaks (Nymphalis antiopa). These are now joined by White Admiral butterflies and by Common whitetail dragonflies patrolling overhead. I am used to seeing this floating butterfly assemblage traveling linearly on their feeding searches along bushes on the road’s sides, but here they fly in their natural setting. The butterflies follow large spiral flight paths broken by and traveling through the dense shrubs. In this setting, their frenetic sharp turns and chaotic shifts are necessary to navigate this complicated scene, and this explains these seemingly purposeless motions on their flights over the road. In this manner, the butterflies explore every possible hiding place in which a flowing blossom might be found.

At each of my stops along the stream, I see about five butterflies, and together with butterflies along the road, I estimate that there about 100 butterflies in the first mile road. Two Painted Lady butterflies (Venessa cardui) are also patrolling the roadside bushes. What flowering plant these butterflies are searching in the shurb understory is a mystery. The daytime flowering blossoms of spring are past, and only a few Foxglove beardtongue flowers remain open producing nectar. The only substantial flowering plant left is Yellow sweet clover. But the stands of this weed that line only the roadsides are fading, and on any one plant only one-third of the blossoms found at their peak are viable.

The fierce post-solistice sun begins to affect tree leaves. One or two Gambel’s oaks and Norway maples have a brace of leaves that are browned and shriveled at the edges. Once damaged, their leafs curl up, and the crabapple tree at the upper end of Pleasant Valley near mile 1.7 shows similar signs of stress. But the deciduous trees’ principal defense against the loss of water from heat and sunlight is a waxy layer on the upper surfaces of trees. This is best seen on the leafs of the western River birch trees. At the right angle to the Sun, their canopy flashes dappled green light for leafs titled away from the light and a blinding silver-white light for those at appropriate angle of reflection. University of Sussex ecologist Hartley notes that the waxy layer provides another benefit: it is some tree’s defense against caterpillars (Hartely 2009). Although caterpillars have evolved specialized feet to grasp leaf surfaces, caterpillars have a hard time walking over the wax layer, they fall off, and the plant is preserved. This may explain the caterpillars sometimes found along the road in the last week. I had supposed the caterpillars had crawled onto the roadway, but perhaps they have slipped and fallen from above.

Returning down canyon from milepost 1.5, insects are backlit by the Sun, and this makes them easier to see. At mile 1.1 near the entrance to lower Pleasant Valley, 30 to 40 Common whitetail dragonflies are circling between 50 and 100 feet above ground. Between the road surface and fifty feet, there are none. In cool places beneath the shade of trees, the prey of the dragonflies, groups of up to 100 gnats float. A small, immature desert tarantula (Aphonopelma chalcodes) scurries into the bushes.

Also mile 1.1, I hear raptor screams, and this repeats my earlier experience of June 21st. They are the unmistakable calls of two Peregrine falcons (Falco peregrinus). This time I travel back up canyon to get a better view, and below the eastern canyon wall near mile 0.8, more than a quarter-mile away, two peregrines are driving a smaller bird away from the canyon sides. There loud screams travel coherently through the calm summer air. This may be where the peregrines are nesting this season, but that side of the canyon does not have the steep cliffs found on its western walls. I note to watch this area closer to see if a nest can be confirmed.

* * * *

Per Thoreau’s “Journal” on June 25th, 1852, he sees a rainbow in the eastern morning sky. He opines that younger birds are duller in color in order to protect them from predators. He hears a bobolink and a golden robin. He sees wild rose and butter-and-eggs. He notes that in cool air, the ridges on distant mountains are more distinctly seen. He describes a moon-light walk. On June 25th, 1853, he finds two bushes of ripe service berries and associated cherry birds. On June 25th, 1854, he sees a bittern. On June 25th, 1858, he sees two or three young squirrels playing. He observes how objects including grass and water skimmers cast lenticular shadows on the bottom of a river. He again notes how the lighter undersides of leaves illuminate dark sprout forests.

* * * *

On June 25th, 1946, City Water Commissioner D. A. Affleck closed all lands in lower City Creek and above 14th Avenue to entry in order to prevent the possibility of grass fires (Salt Lake Telegram). Campfires were prohibited in upper City Creek Canyon (id). On June 25th, 1913, City officials plan to inspect the headwaters of Salt Lake valley canyons for water purity as part of a plan to develop more water sources (Salt Lake Telegram). On June 25th, 1896, new silver and lead ore bodies were discovered in upper City Creek Canyon about one mile from the old Red Bird Mine on Black Mountain (Salt Lake Herald). Mining work continues at other mines in the Hot Springs mining district, which includes City Creek (id). On June 25th, 1892, an old, destitute woman who had been living in cave in City Creek Canyon was sent to the hospital (Salt Lake Times).

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June 13, 2017

June 5th

Hopping Horsetail Pollen

4:15 p.m. It is the third day of an unusual early heat wave where daytime maximum temperatures reach 95 degrees Fahrenheit, while the average maximum for early June is about 80 degrees. In the heat, fewer birds sing. There is one Warbling vireo near picnic site 1 and a single Black-headed grosbeak and a few Song sparrows below milepost 0.5. On this Monday, people follow suit: the heat deters them and there are only a few runners and walkers along the road. Despite the heat and yesterday’s end of canyon snowmelt, the stream still runs high. But at mile 0.6, there is a distinct thermocline: a breeze picks up and temperatures are ten or fifteen degrees lower than in the city. The birds respond accordingly.

The season’s first unambiguous Weidemeyer’s Admiral butterfly (Limenitis weidemeyeri latifascia), a black butterfly with white wing bars, floats by at milepost 1.0, and this followed by a Blue dasher dragonfly. A new white butterfly is seen, but it is too fast and appears too briefly to identify. Two dead brown moths are found at different places along the road that have delicate yellow-orange underwings. They are invasive Large yellow underwing moths (Noctua pronuba).

The heat has also begun to force Wood roses along the road. As they reach maturity, their color starts to lighten, and a day or two later, their blossoms shrivel. More are gone at the lower canyon, the wave of mature roses is slowly moving up canyon. The blossoms of the Solomon’s seal field in the cattail seep at mile 0.7 have shriveled and passed. Across the road, the beginnings of Milk weed plants rise to a foot tall. New crops of horsetails have matured between mile 0.4 and mile 0.8, and they can be distinguished from the still reawakening horsetails that overwintered. These new horsetails are larger in diameter, have a lighter green color, and have larger cone shaped heads. Older horsetails are a darker green, and for the most part, their heads from not yet swelled with pollen for this new spring. On close inspection, the newer horsetail heads release a puff of pollen when disturbed.

Turning down canyon from Pleasant Valley, below the Red Bridge near mile 0.9, an orb weaver spider has woven a large four-foot circular web suspended between boulders and surrounding tree branches. Some of the web’s silken, supporting suspension cables reach six feet over the stream. The web whips wildly in each breeze, but it is effective. The spider has bundled up several insects along its web’s radial branches.

* * * *

In Thoreau’s “Journal” on June 5th, 1850, he smells that the air is full of spicy odors. He sees lady’s slippers and wild pink plants. On June 5th, 1852, he records cinquefoils, and he notes that lupines are in full bloom. On June 3rd, 1853, he again notes that the air is full of fragrance and that meadows are full of sorrel and green grasses. On June 5th, 1853, he sees a pair of nighthawks and their nest, and a blackbird. On June 5th, 1855, he notes sedge grass growing in rock cracks. On June 5th, 1856, he records lady slippers and he examines a cuckoo’s nest.

* * * *

In 2013, Marmottant, Ponomarenko and Bienaimé at the University of Grenoble reported that the 50 micrometer pollen of horsetails have the ability to “walk” (Marmottant, Ponomarenko and Bienaimé 2013). These tiny pollen are shaped like harlequin starfish, except they have four arms instead of a starfish’s five. When wet, the arms of the pollen curl around its central body. As the pollen dries, the arms suddenly unfold and propel the pollen into the air, and once aloft, it can be deposited in a more favorable, moist habitat (id).

* * * *

On or about June 5, 1975, Utah’s first gay pride festival, then called “Gay Freedom Day” was held in Memory Grove at City Creek Canyon (Salt Lake Tribune, June 5, 2008). A small crowd of 300 gathered over beer, burgers and hotdogs. Then they moved to the Sun Tavern. One of the participants of the first festival recalled that people were afraid to attend because they were concerned that bosses, co-workers or neighbors might see them attending. “We knew we were being discriminated against, and it was at least up to us to stop discriminating against ourselves,” the first pride day participant noted.

May 13, 2017

May 11th

Giant Crane Flies

6:30 p.m. Starry solomon’s seal has grown several inches in the last week, and now before twilight, numerous of these plants open their blossoms. At the seep below picnic site 6 (May 6th), six stick-like Giant Western Crane flies (Holorusia rubiginosa). They look like a cross between dragonflies and giant mosquitoes with long extended three inch abdomens, but like the Black-tailed bee fly, are “off” – they have only two transparent wings. Four are smaller, but the two larger are engaged in mating. They facing away from each other, and join at that the rear of their abdomens. Sometimes they can be seen in this ritual dance while flying. Their larvae feed on algae, and the female deposits her larvae in mud, similar to the boggy soil at this seep. Sadly, they live only a few days, and their elongated, spear-like proboscis is suitable for only sipping the small amounts of water and nectar needed to keep it alive for that short period.

The cattail grove, that was removed here last autumn, has begun to regenerate. A small cattail patch has reached almost three feet in height. Below picnic site 2, the year’s first blue penstemon (also called foothill beardtongue) (Penstemon heterophyllus). Penstemons are usually confined to the high meadows of the Wasatch Front Mountain Range, and there at the height of summer below the tallest peaks, great fields of blue can be found. This single explorer is a welcomed reminder of the high mountains.

Near picnic site 1, I stop and listen for bird songs, and tracking one back find a bright male red and yellow Western tanager perched on the highest dead branch of a tree. The bottom of the tree is in twilight, and the tanager enjoys the last yellow rays of setting sunlight.

At Guardhouse Gate, the circular class=”sigil_index_marker” title=”Orb weaver spider” orb weaver spider web is gone (May 7th). Orb weaver’s rebuild their webs each day, but a tangled, chaotic web has taken its place. No spider is present, but the form of the web suggests it was constructed by a house spider.

* * * *

On May 11, 1896, the Salt Lake Tribune cryptically reports that the dry bench (Avenues) farmers “are getting the best of it this year”, and this probably reports a wet spring. That year, 1896, was a flood year, and this year, 2017, is also wet. The hillsides above the Avenues and that surround the canyon are now covered in deep green grass.

May 10, 2017

May 7th

Iridescent butterflies

4:00 p.m. Red-ozier dogwoods are blooming. Gambel’s oak trees at picnic site 1 have leafed-out to between two and four inches, but some of these oaks higher at mile 1.0 have no leaves. At Pleasant Valley, grasses are twelve inches high and move in waves in response to breezes. The high canyon walls are all covered in these green waves. Along the Pipeline Trail, red maples have leafed out to four inches. Mullein stalks are beginning to rise. Along the Pipeline Trail, 20 or 30 birds can be heard, but only yesterday’s male Black-chinned hummingbird puts in an appearance at its usual post on the powerline. No soaring raptors are seen today.

The thirty or forty butterflies in the first mile are dominated by Orange Sarah tops and Desert Elfin (Incisalia fotis fotis) butterflies. Below picnic site 1, an unidentified red-brown caterpillar hangs from a Box Elder tree by a twenty-foot long silk thread, and as the wind blows it sways back and forth in large five foot arcs. It does not know whether to go further down or up. At picnic site 3, an unidentified beetle lites onto a table, and in a ray of sunlight, a patch on its back radiates a bright lime green. Near mile 0.5, a small black ant drags a dead lime green caterpillar back to its nest. Along the Pipeline Trail, a Common sulphur butterfly moves between and drinks from Arrowleaf balsamroot blossoms, and more than ten Stink bugs are active on the trail. I miss nearly stepping on one that is laid out, legs splayed wide, on the trail. My foot alarms it and it springs up and lands in a defensive posture. Back at the Guardhouse Gate, I notice a Cabbage white butterfly fly into a bush, inexplicably struggle, and then frenetically fly off. Close examination shows the circular web of an orb weaver spider (Araneus sp.). This unidentified spider has wonderful orange, white and black spotting on its abdomen, but I am unable to photograph. My autofocus camera only sees the background and refuses to make a sharp image of the tiny spider in the foreground.

Just before Guardhouse Gate, two mallards, one-male, one-female, are standing right next to the road unafraid of humans. The male is half-asleep and appears contemptuous of people. The female is feeding on roaches under the leave litter. She digs through the leaf litter and rapidly opens and closes her beak. This separates the chaff of the dead leaves from the wheat of the small bugs. In the Guardhouse Gate parking lot, an immature Rock squirrel is browsing in the middle of the road. I pull out the car and chase him back into the brush with flashing lights and a honking horn. I am teaching the squirrel to be afraid of cars. For this squirrel, there will be no repeat of finding it dead on the road, as seen last summer.

* * * *

Butterflies also have ultra-violet vision used in differentiating flowers, but some may use iridescence and the uv spectrum to communicate between themselves (Doucet and Meadows, 2009; Buront and Majerus, 1995). Butterfly wings are covered in miniature scales that like the feathers of birds make colors have diffraction. In 1968, an experiment of Obara and Hidaka at the Tokyo Institute of Agriculture and Technology demonstrated that male Cabbage White butterflies locate their mates primarily by visual clues (Obara and Hidaka, 1968). They sealed females and male dummy butterflies in Petri dishes in order to prevent the males from finding their mates by smell. Since male and female Cabbage whites look nearly identical in the visual spectrum, how could the males tell them apart? Ultra-violet photography revealed that the wings of female Cabbage whites are white or patterned and the males are totally dark. On 2008, Obara and colleagues repeated this experiment, but noted that females have subtle changes in their UV color during the summer, and males preferentially mate only with the summer-colored females (Obara et al 2008). In 2000, Knuttel and Fiedler at the Universitat Bayreuth suggested that this was not a universal principle. They found that many species of butterflies appear different in the visual and uv light, but the variations within species where larger than between species and were not so great as to be a means discriminating between or within species (Knuttel and Fiedler, 2000; Buront and Majerus, 1995, same). Iridescent differences in the visual spectrum is dominant in butterflies when distinguishing between individuals (id). Butterflies also have iridescent colors in order to confuse predators or to warn them that the insect is poisonous (Doucet and Meadows, S124).

* * * *

On May 7th, 1996, Utah Partners in Flight plan migratory bird watching in City Creek Canyon (Salt Lake Tribune). On May 7th, 1910, the Salt Lake Telegram published a photographic spread on City Creek Canyon and extolled the canyon’s virtues. The Telegram argued for a City Commission proposal to widen the road using prison labor and to make other park improvements (id).

November 5, 2016

November 5th

Filed under: Orb Weaver Spider, Uncategorized — canopus56 @ 9:21 pm

A Cat’s Face on the Road

4:30 p.m. Along the road at mile 0.4, a Halloween phantasmic is crawling across the road: a spider with yellow-orange orb-shaped shell on its back that is suggestive of a cat’s face. It is a female Cat’s face orb weaver (Araneus gemmoides). My insect guide states that they are commonly seen in late October as they migrate seeking a place to hibernate for the winter. This common western orb spider looks like a crab, and a mark of its primitive evolutionary history are the hairs that cover its leg. The cat’s face spider weaves a circular web that is held in place by radial scaffolding. In the canyon, webs of the orb spider can be seen during the summer strung between thistles below the red bridge near mile 0.9. Although harmless to people, they are a fearsome predator of flying insects that feeds on wasps and bees captured in its web.

In 2007, evolutionary biologists Vollrath at Oxford and Selden at Kansas University suggested an alternative theory that predatory spiders like the orb weaver were a driving force in the evolution of flying insects because spiders and flying insects began to exponentially diversify into many new species before the arrival of flowering plants. The current generally accepted theory is that flowering plants, which began to dominate forests about 145 million years ago, were the primary driver of the evolution of wasps and bees. Ants evolved into flying insects in order to exploit a new food source: the nectar of flowering plants. According to the new theory proposed by Vollrath and Selden, the oldest spiders were ground dwelling when they first learned to spin webs, as some spiders in the canyon still do today. In response, ants sprouted wings, learned to fly, and evolved into wasps in order to avoid the horizontal webs of ground spiders. Orb spiders responded by chasing the wasps into the sky. They learned to climb thistles and other plants and to weave their vertically placed webs. Later the wasps co-evolved into bees. Vollrath and Selden acknowledge that this is an evolutionary “just so” story. Spider webs are ephemeral objects that disappear after a few days and they are not preserved in fossils. The record in the rocks is too sparse to know when the first spiders began to spin ground webs or when they took to spinning vertical webs strung between plants.

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