City Creek Nature Notes – Salt Lake City

July 30, 2017

July 21st, 2016 – End of Cyclical Year, Revised and Reposted

Microorganisms, Moss, Lichens, Glaciers, and Climate Trends

(Revised and expanded after lichen identification completed.)

3:30 p.m. It is another day intense summer heat, and as I pull into the parking lot, I take notice of a large Limber pine (Pinus flexilis at the lot’s end, south of the row of cultivar Horsechestnut trees. The Limber pine, Narrowleaf cottonwoods and the Horsechestnuts are among the largest plant organisms in the canyon, excepting some of the 50 foot diameter copses of Gambel’s oaks that may be one large, genetically identical sister plant. A bizarrely twisted, immature Limber pine hides behind to the east of side of the Guardhouse Gate building, and just past the gate, another conifer, a mature 70 foot tall native Engelmann spruce (Picea engelmannii). Key taxonomic differences between the two is that round pine needles occur in groups of two and flat fir and spruce needles are single. At mile 1.7 at picnic site no. 12. There a forty foot tall Rocky Mountain juniper (Juniperus scopulorum) is flanked by two taller Engelmann spruce trees. Although native to northern Utah, these three trees have been artificially planted to provide shade for picnic area.

Jogging up canyon about 100 yards up from the gate, I pass a deadly Bittersweet nightshade plant with small 1.5 inch green fruit. Splitting one of the fruit open, it is full of 1 mm bright orange larvae, and testing a few more, they are all infected. Given the number of young children that pass this spot, this is probably not a good place for a poisonous plant.

In the heat, I jog alone through an empty road, except for bicyclists. Near mile 0.3, sounds in the Gambel’s oak forest undergrowth betrays an yearling Mule deer stares back through the leaves. It is waiting for me to pass, so it can reach the stream and water. A bicyclist streaks unaware of its presence. A slight anabatic up-canyon wind provides a brief relief.

Beginning at mile 0.5 and the pond at picnic site 5, I collect the sponges placed in the stream and seeps on July 15th. The sponges have been collecting microorganisms for several days. I have looked at water samples from the stream under a microscope several times since May, but have never seen any microorganisms. That is a testament to how pure City Creek Canyon water is. My microorganism observing guide suggests using the sponges to trap organisms over time. The sponges also provide a protected framework that might appeal to microorganisms by providing shelter. The first sponge was located below the pond at picnic site 5, and it was placed under a cover of rocks such that stream water would continuously flow through the sponge. The first from the stream is a dark brown – a good sign. The second collected from the seep below picnic site 6 and the third is retrieved from the watercress seep also below picnic site 6. All three are a dark brown-grey color; the sponges have worked.

At the seep below picnic site 6, the Horsemint is in full bloom, and I count 32 Cabbage white butterflies feeding on them. A single Central bumble bee (Bombus centralis) collects among the butterflies. These are joined by an orange Mexican queen butterfly. I stand mesmerized by the glade for a few minutes. Nightshade is now also blooms in this glade.

Carpenter bee (Xylocopa californica) reappear after their first spring flight. Uniquely, they fly in a circular pattern closely around me twice, and having rejected me as potential food, they fly off with purposeful intent.

Proceeding again up canyon through the heat, only a few birds are heard at some distance from the stream. I cannot distinguish their calls, except for the nasal cawing of a Red-breasted Nuthatch (Sitta canadensis).

At mile 1.1, I stop where a large rock ledge overhangs the stream and admire a tremendous cottonwood cross, a Populus angustifolia x fremontii S. Wats. This 100 foot tree with a twenty-four inch trunk betrays it hybrid nature through two suckers, each 8 inches in diameter at the base. The parent tree has ovate leaves typical of the cross. Those leaf forms continue on one of the suckers, but at its very tip is one perfectly formed triangular Fremont popular leaf. Mid-way up the second sucker, that is also covered in hybrid leaves, is a bracket of perfectly formed thin Narrowleaf cottonwood leaves. This tree must be at least 100 years old, and perhaps it is older and witnessed the arrival of the Euro-American colonists in 1847. At a few minutes of enjoying this tree, I notice that it is looking back at me. More precisely, another Mule deer is on the rock ledge on the far side of the stream, and it is intently following me. I continue up canyon so it can reach water unmolested.

At mile 1.2, I turn down-canyon on the Pipeline Trial in order to photograph some of the lichens on rocks that line the trail down to where it is perpendicular to the Red Bridge and Chimney Rock. The Gambel’s oaks that border each side of the trail are covered in a ubiquitous dusky orange lichen that is found throughout the canyon. Here the rocks are principally volcanic breccia or limestone conglomerates. The first rock has lichens that are three inch diameter turquoise dollops with raised fruiting centers. The second rock has a large turquoise dollop on one corner and fire yellow bright lichen on one face. This rock also has small dark black lichen circles. The third rock has bright orange circles with darkened brown centers. The fourth has similar bright orange two inch dollops with fruiting orange centers. This same orange rock lichen is common in the canyon. For example, it covers parts of the rock bridge at Weeping Falls near mile 5.2. This bright orange lichen only appears on rocks, and its dusky orange brother keeps to the trees. Near the end of this segment, a gully provides more shade an water. Here, the rocks are covered in complex moss complexes, and unidentified green-black small-onion like moss with fine white hairs.

Continuing up canyon to a western gully near mile 2.3, there is another slope with favored lichen rocks. Here the rocks are sandstone based. In the gully, the first rock is a kaleidoscope of circular lichens colored bright orange, turquoise, and black. The next rock is covered with a bulbous green-black moss with fine white hairs. This is followed by a rock covered in turquoise-green lichen that has a darker brown center. Finally, two foot square areas of an unidentified green-black bulbous lichen attach to a rock ledge’s horizontal surface. Looking over some of my other lichen photographs above milepost 5.0, two prominent upturned limestone ledges stick out next to the road. On these a montane grey-milk lichen that look like delicate leaf petals cling to the stone.

This is all a riot of color mixed with abstract design. Lichen are oldest and, for me, they embody the most alien of terrestrial life. I also hold them in the highest respect because they are all a form of extremophile. They thrive on canyon rocks that both bake to temperatures over 150 degrees during the summer, and they continue to reproduce during the subzero cold of deepest winter. They live on the surface of barren rocks and take all that they need from the passing air and rain. And, what else the need in terms of minerals, they obtain by dissolving the solid rocks to which they attach. Moss are less of an extremophile, but tree moss are one of the few plants that continue photosynthesis through the depths of winter (January 10th).

Returning down-canyon near mile 1.3, ahead, I again here the screeching of a Peregrine falcon. Two falcons are chasing two unidentified hawks away from the sandstone cliffs on the east wall of the canyon near mile 1.0. One falcon easily chases a hawk up canyon and over the ridge. The second hawk begins to climb in lazy, large circles, and the remaining peregrine follows. The peregrine raises higher and then stoops the hawk, all the while screeching loudly. This continues for about 15 minutes. At times I loose sight of the pair as they circle overhead with the Sun behind them. The spring sky is a deep blue, but today, the summer sun makes the atmosphere a white turquoise.

Continuing down-canyon, at picnic site 5 where I collected one sponge, an innovative young couple using long lengths of climbing webbing, have suspended two bright Central American woven hammocks over the stream. They lay side-by-side enjoying the stream-cooled air.

At Guardhouse Gate, there are the cut fireplace-sized remains of a large tree. A quick count of its rings indicates the tree is over one-hundred years old. As the the city cuts down infirm trees in the canyon, they leave the carcasses here as free firewood. The cause of this tree’s demise can be seen in one segment of log – it is riddled to the inner pith with boring beetle tunnels. To supplement my gathering of water borne small life, I also collect from the logs’ surfaces, samples of Green tree moss (probably Orthotrichum sp.) and of orange, black and turquoise lichens.

The lower flood retention pond is full of algae mats. A family of mallards graze on the greenery. The chicks, who a few weeks ago where only four inches long, are now twice that size.

At home, I examine water from the three sponges in under a microscope at 60 power of magnification in order to see some of the smallest plants and animals of the canyon. All of the samples consist mostly of bits of algae, some of which are strung on the ends of mold filament, pulverized bits of plant, and specks of silica. No moving protists are seen. A few rectangular-celled with diatoms with well-defined glass-like walls of the genus Fragellaria are found. Two circular diatoms of the genus Stephanodiscus are seen. Finally, a single, transparent perfectly formed leg of an insect exactly fills the eyepiece and then floats away. This is clean City Creek water.

At home and through the hand-lens, the leaves of the moss, which are present both on trees and on rocks in the stream, reveal their earlier evolution as compared to the leaves of the surrounding trees. They are thin and transparent sheets of green cells, and they lack any vascular features found in true leaves.

Under the hand-lens, where the black lichens interface with the tree’s bark, a separate white hyphae through which digestion occurs. Lichens are composite organisms of algae or green bacteria living symbiotically with fungi. Through the hand-lens, one can see two colors, representing the two organisms in the turquoise and orange lichens. The turquoise portion of the turquoise lichen is also surrounded by white hyphae. The second color is green, and through the lens, these resolve as small bits of algae. That lichens exist on almost all of the trees in the first two miles of road is a good sign. Lichen are sensitive to air pollution and will disappear if Salt Lake’s air quality severely deteriorates over a long period.

The length of the day have changed noticeable from June 20th’s summer solstice. Sunset comes an hour earlier around 9 p.m.

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St. Clair, Newberry and Nebeker (1991 and 1995) provide a comprehensive list of Utah lichens. They and Flowers (1954) describe which species of lichen are common in various northern Utah habitats, including for the scrub oak forest of Gambel’s oaks, the higher subalpine habitat of Quaking aspens, and the montane habitat of conifers. Brodo of the Canadian Nature Museum and Sharnoff and Sharnoff of the Missouri Botanical Gardens published the definite photographic identification guide for lichens: their massive 2001 “Lichens of North America”. They note common lichen species for the Gambel’s oak forest include Lecanora hageni, Phaeoplzyscia orbicu/aris, Physcia adscendens, Physcia dubia, Physcia stellaris, Plzysconia grisea, Xanthoria fallax, and Xanthoria polycarpa. Using these sources, my descriptions and photographs match with the following scientific names:

List of Lichens

• Hooded sunburst lichen (Xanthoria fallax): This is the dusky-orange lichen that covers most of the Gambel’s oak trees in the canyon (Brodo, Sharnoff and Sharnoff, 744).

• Pin-cushion sunburst lichen (Xanthoria polycarpa): This is the bright orange lichen that covers many rocks in the canyon, including the stone bridge at mile 5.2 (Brodo, Sharnoff and Sharnoff, 746).

• Stonewall rim-lichen (Lecanora muralis): This lichen was the even-toned yellow-green (turquoise) circles on rocks along the Pipeline Trail (Brodo, Sharnoff and Sharnoff, 383)

• Sagebrush rim-lichen (Lecanora garovaglii). This is the yellow-green (turquoise) lichen with a darker green center on a rock along the Pipeline Trail (Brodo, Sharnoff and Sharnoff, 380).

• New Mexico rim-lichen ( Lecanora novomexicana): This darker yellow-greenish lichen with yellow fringes was found in the gully near mile 2.2 (Brodo, Sharnoff and Sharnoff, 384).

• Gold cobblestone lichen (Pleopsidium flavum): This is the bright yellow lichen on one rock along the Pipeline Trail. (Brodo, Sharnoff and Sharnoff, 578).

• Powder-tipped rosette lichen (Physcia dubia): This is the delicate leaf-shaped lichen on the limestone vertical fins near mile 5.0 (Brodo, Sharnoff and Sharnoff, 554).

Like today’s Great Salt Lake (May 26th), ancient Lake Bonneville’s water levels and glaciation of the Salt Lake’s canyons at the end of the last ice age gives clues as to the climate of the Salt Lake valley and the canyon. That record is hidden within the valley’s rocks and trees. In 2015 and updating a prior study from 1997, Oviatt at the University of Kansas reconstructed date ranges in which ancient lake rose and fell by radiocarbon dating organic material in tufa deposits along the lake’s former shorelines. He concluded that Lake Bonneville began its rise about 30,000 years ago (id., Table 1). Between 15,000 and 18,000 years ago, Lake Bonneville reached its maximum height at about 5,100 feet, or near the northern end of Pleasant Valley in the canyon near mile 1.7. Following the failure of the Red Rock ice dam in Idaho, the Lake drained to the Provo Shoreline, which is Bonneville Drive and 11th Avenue in the City. Other the next 15,000 years, the lake gradually declined to the current level of the Great Salt Lake (id).

In 2011, Laabs, Marchetti, and Munroe and colleagues used residual Beryllium 10 isotopes in rocks, taken from the glacial moraines in Little Cottonwood Canyon in Salt Lake valley and American Fork Canyon in Utah valley, in order to date when glaciers retreated up from the ancient lake’s shores. An ongoing question existed amongst geologists, based on conflicting earlier studies, concerning whether the Salt Lake glaciers receded before, coincident with or after the end of the last Ice Age and-or before, coincident with or after the end of the peak level of Lake Bonneville. Figure 1 of their study shows the area of glaciation stretching from American Fork to the south and Farmington, Utah in the north, thus, including City Creek Canyon. They concluded that glaciers covering the Salt Lake valley canyons started to retreat 15,700 plus or minus 1,300 years before the present, either during or shortly after the maximum 5,100 foot shoreline height of ancient Lake Bonneville. Their confidence interval overlaps the 15,000 to 18,000 years before the present found by Oviatt for the maximum height of Lake Bonneville. Deglaciation started about 4,000 years after the end of the continental Ice Age at 18,000 years ago. Because the lake reached its maximum and retreat of the local glaciers started after the end of the Ice Age, Laabs, Marchetti, and Munroe et al concluded that the local climate between 18,000 and 15,000 years ago was wetter than thought by prior geologists.

That there were glaciers in City Creek Canyon below Grandview Peak and at the canyon’s final hanging valley (September 8th) seems evident from an examination of any terrain map and hiking the canyon. But to my knowledge, there are no studies dating the glacial deposits in City Creek Canyon. Van Horn and Crittenden’s geologic map shows no surficial glacier features (Van Horn and Crittenden, 1987, U.S.G.S. I-1762). Perhaps there was a lighter ice sheet over the canyon 15,000 years ago, but it was insufficient to crave the bedrock.

The Engelmann spruces and other pine trees that live in association with the spruces, tell the history of Salt Lake valley’s and the canyon’s climate for the last 13,000 years before the present. In Little Cottonwood Canyon, Engelmann spruce share the glacial scoured hillsides with Limber pine (Pinus flexilis). Engelmann spruce is more tolerant of wet earth and colder soil temperatures, and Limber pine is more tolerant of dry earth and warmer soil temperatures. Thus, as climate changes occur over thousands of years, the relative amount of pollen left in soil layers beneath their canopy gives a general indication of weather in the distant past. In 1979, Madsen and Currey at the University of Utah used a bog in Gad Valley near Snowbird Ski Resort to reconstruct Utah’s late Holocene climate (Madsen and Currey 1979). Based on moraine deposits, the maximum extent of glaciation that extruded glaciers into the Salt Lake valley floor occurred about 25,000 years ago. After a period of warming, a second smaller glacial period ensued and Madsen and Currey, using the bog at Gad Valley places that around 12,500 years ago. Then glaciers within Little Cottonwood Canyon retreated and disappeared. A similar bog in Albion Basin at the top of Little Cottonwood is dated at 9,500 years (id, 258). Using the ratio of Engelmann spruce and Limber pine in the Gad Valley bog, Madsen and Currey were able to reconstruct the relative climate of the canyon, and by extension the Salt Lake Valley and City Creek Canyon, for the past 12,500 years. Between 13,000 and 8,000 years before the present, the valley’s climate was cooler and wetter than today. Between 8,000 and 5,000 before the present, advancing Limber pines indicate a warmer and drier climate than today. Then there was a brief period in which temperatures greatly declined, followed by a quick warming and a gradual decline to today’s cooler temperatures with respect to the 13,000 year mean (id, at Fig. 6 and 265). In contrast, precipitation has been on a gradual decline for the last 6,500 years and is currently near the 13,000 year mean (id). These are consistent with Grayson’s climate divisions for the Great Basin Holocene generally: 10,000 to 7,500 years before the present (early), 7,500 to 4,500 years before the present (middle), and 4,500 years before the present until today (late) (Grayson, Chap. 8).

Over the last 4,500 years, a picture of trends in Salt Lake City’s local climate can be developed from tree ring, Gad Valley bog pollen, and other climate research. Since 4,500 years before the present, there was a brief period in which temperatures greatly declined, followed by a quick warming and a gradual decline to today’s cooler temperatures with respect to the 13,000 year mean (Madsen and Currey, Fig. 6 and 265). It is now colder than average than over the last 13,000 years. The Little Ice lasted from about 1300 C.E. to 1850 B.C. There were highly variable swings in temperature during this time, but those changes were not global, but regional (Solomon et al 2007; Houghton et al 2001). In Utah, the Little Ice Age ended in 1850 and was followed by the most severe winter in Utah history, the winter of 1855-1856.

Since 4,500 years before the present, precipitation has been on a gradual decline for the last 6,500 years and is currently near the 13,000 year mean (Madsen and Currey). From 1492 to the present, the tree rings show that persistent, severe droughts were far more prevalent in the distant past than in the 150 years of Euro-American presence in northern Utah (Bekker et al 2014). Variability in Salt Lake City precipitation since the 1960s, including severe drought in the 1960s and peak flooding in the 1980s, is tied to the Pacific Quasi-Decadal Oscillation, an 11 year cycle of drought and heavy precipitation tied to ocean temperatures off the coast of California and Japan. The level of the Great Salt Lake acts as a recorder of climate, and the Lake’s level has been recorded continuously since 1875 (USGS, 2017a, USGS, 2017b). In the summer of 2016, it dropped to a new historical low of 4,190.1 feet (id).

In 2010, Wang and colleagues at the Utah State University associated the Pacific Quasi-Decadal Oscillation (PQDO) with a northern Utah three-year leading precipitation and a six year leading level of the Great Salt Lake (Wang, Fig. 4 at 2166). In the association with the level of the Great Salt Lake, PQDO warm phase peaks are associated with the lowest lake levels and PQDO cool phase troughs are associated with the highest lake levels. In 2013, DeRose, Wang and colleagues used tree rings to reconstruct the level of the Great Salt Lake back to 1429, and they associated the lake’s level to the pacific oscillation back to 1700 (DeRose 2013). In recent years, the PQDO has been good for Utah. While California has suffered severe drought, the PQDO has kept annual precipitation relatively higher in Utah (IWWA Project).

The PQDO has not had a phase change since 1997 and the change to a heavy precipitation pattern is overdue. Despite heavy winter snowfall in the high mountains during the winter of 2016-2107, Utah remains in an extended drought with unseasonably warm summers.

Future uncertainty is added by the effect of global warming. Has global warming disrupted the Pacific Quasi-Decadal Oscillation? What will its future impact be? However, even excluding global warming, Salt Lake City and Utah are on a path towards relatively hotter weather and declining water supplies as compared to the past.

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On July 21st, 1942, the City banned the entire north bench of Salt Lake City to entry due to fire hazard, but access to City Creek Canyon would remain open (Salt Lake Telegram). On July 21st, 1906, the Deseret Evening News published a picture of a 10 foot snow bridge across City Creek Canyon about nine miles up the canyon. On July 21st, prize fighter Tommy Reilly trained by taking a long run up City Creek Canyon (Salt Lake Telegram). On July 21st, 1903, about 100 Ute Tribe members gathered for an annual celebration at the mouth of City Creek Canyon (Salt Lake Herald). (In the present, the Ute Tribe holds an annual meet at Liberty Park.)

May 9, 2017

May 6th

Wizards of the Canyon Soundscape

7:00 a.m. The entrance to the canyon along Bonneville Drive is closed today for one of the many social 5K runs that occur during the summer. This adds an extra mile jogging along the drive to reach Guardhouse Gate. As I start, the sun line is just beginning to descend the snow capped peaks of the western Qquirrh Mountains and the small sliver of the southern tip of the Great Salt Lake reflects slate blue. The clear western sky shows the last vestiges of dark slate band of the Earth’s shadow retreating from the sun. Along the first stretch of road there are many sage brush bushes that provide cover to chukars. I stop to pick and crush a bracket of this pungent bush to remind myself of what Utah smells like during the heat of summer. About one-half mile from the gate and around a bend, the canyon explodes with the sounds of stream and birds. Although hidden, a male Lazuli bunting peaks from behind some red maple leaves, singing loudly. His colors are muted, since he perches in early morning shadow of the canyon’s east ridge. The sound of the stream is overwhelming, and this indicates the vernal season’s heat is melting the high snowpack. At the gate, the parking lot is full, and includes the enormous truck of the wild turkey bow hunter (May 4th). I must have just missed the race organizer’s closing of the road.

Along the road, the grasses are now twelve to eighteen inches thick, and the first quarter-mile is nearing full leaf out. Near mile 0.3, I look up through the trees to the step slope above, and there a young female mule deer idly grazes on the new grass. I stop to watch and after some minutes, she takes notice of me, stares back, and knowing that it is not hunting season and she is in no immediate danger, she slow walks and disappears into the Gambel’s oak forest. A bird loudly chirps from a nearby tree, and I catch a fleeting glance of black, white and red-brown from below. It is probably a Rufus-sided towhee (Pipilo maculatus). I count about forty or bird separate birds calling the forest thickets in the first mile.

I am not a morning person, most of my daily observations are in the afternoon, and the morning spring canyon is a new place. The warm morning light crawls down the western ridge of the canyon, and makes the thick grasses of spring bathed in an inviting green light. Although it is a pleasant high fifties along the road, one can feel the advancing daytime heat in the seventies approaching. Between mile 0.5 and 1.0, large overhanging trees in partial leaf-out form a series of green tubes through which the rising south-eastern sun penetrates. The lighted end of these tubes with the darkened green leafed foregrounds reminds me of the religious ceiling paintings of European cathedrals. I am overwhelmed by the beauty of it all.

In this half-lit morning reflected light, the canyon has a different character. I have misjudged the Starry solomon’s seal. In the afternoon, I have found two or three open out of an estimated 20,000 plants (May 4th). This morning, most are open, and I easily count 200 open blossoms in the solomon grove surrounding the seep below picnic site 5. The number of active birds is astounding, and a multiple of several times over my afternoon encounters.

At the entrance to Pleasant Valley, I run into the Tracey Aviary sponsored birding, a course directed by and led today by aviary biologists Bryant Olsen and Cooper Farr. I am happy to find the group; I have followed their Cornell birding logs in the canyon for some years; and in the spring, they regularly return to the canyon. Other seasons draw them to other habitats. Traveling down canyon, there seven group members including the leaders, and their five students are a diverse group that range from their thirties to eighties. They allow me to tag along as they proceed down the Pipeline Trail for the one mile walk back to the parking lot. Since I have been frustrated for some years in identifying the thicket hidden birds by sound, and I hope to gain some insight into the process by watching and learning. I quickly learn that I am in the presence of masters. Many birding skills quickly become apparent that explain the large number of birds that they record each week in the Cornell University E-bird log system (Cornell Ornithology Laboratory 2016).

First, birding in groups greatly increases detection. I first encountered this in amateur astronomy. Looking for detail in nature, which involves rare events, is more likely with more eyeballs that can cover the whole sky. In addition to the chance of making a sighting, the ability to perceive rare events also differs greatly by both the ability to perceive and by the knowledge to understand what one is seeing or hearing. The seven of the birders stare intently towards a sound coming from a clump of leaves, and one or two of the seven will first detect the bird, and then direct the others to it. Seven sets of eyes scanning the sky’s dome catch fleeting glances of bird movements in opposite directions, and this greatly increases the number of exclamations that one or another of some species has been seen.

Second, time explains the groups many sightings. As we descend the trail, younger runners and bikers wisk by at six to fifteen miles per hour. They traverse the mile of Pipeline trail in five to ten minutes. When I was younger, I has one of these. They smile as they pass, confident in their belief that in their superiority that their youthful ability to exercise makes them the most important denizens of the canyon. My slow jogging takes twenty minutes, but the birding group takes about one and one-half hours to walk this mile. Perception and time are inversely related. The slow see more; much more. Chance visual sightings reveal common sightings such as the cliff-soaring Red-tailed hawks. In this way, the group quickly seeings a Peregrine falcon resting on the top of the western massif at the entrance to Pleasant Valley and a brood of cliff dwelling Violet-green swallow (Tachycineta thalassina) living nearby in the crumbling deposits of Van Horn and Crittenden’s Triassic conglomerate No 2. sandstone. Are these the peregrine’s prey? Peregrines prey on many of the plentiful birds and mammals in the canyon, including mallads, swallows, Mourning doves, Northern flickers, starlings, American robins, Black-billed magpies, American crow, hummingbirds, owls, mice and Rock squirrels. Thoreau used the Peregrine’s historical name – the duck hawk – and Audubon memorialized this predator-prey relationship in a noted 1827 oil painting (Audubon 1827). The peregrines are in turn fed upon by larger birds of prey like Bald eagles and Red-tailed hawks. The birding group has great interest in following the falcon back to its nest, since these birds, although removed from the United States endangered species list in 1999, remain popular and are known to raise young near Pleasant Valley.

Third, these are the wizards of the canyon’s bird soundscape. Raw knowledge, expertise, and practice allows the group to identify many birds by sound alone or first by sound and then by sight. A member will hear a call of interest, and all will stop intently listening while leaning in one direction; some cup hands around their ears. Someone will call out a name, there is a discussion, and then a final determination is made as to the species. Sometimes, this is accompanied by a pointing figure and the exclamation “There it is!”, and all binoculars are raised in unison. I humbly learn the calls of one or two common canyon residents, like the chirping of the Rufus-sided towhee, and can notice distinct obvious sounds, like the wing-beat of a passing Broad-tailed hummingbird (Selasphorus platycercus) and the obnoxious squawking of the Red-breasted nuthatch (Sitta canadensis). But the group’s ability to identify unseen colorful birds by sound alone is astounding. They hear a Green tailed towhee (Pipilo chlorurus), an Orange-crowned warbler (Vermivora celata), and a Western tanager (Piranga ludoviciana).

The group’s ability is distinguish between similar calls is uncanny. I have a particular interest in the rapid chirping call of the Rufous towhee. Later at home, I compare audio recordings and spectrographs of several species found along the trail that all include to my uneducated ears, subtle variations on a series of four to six rapid fire trill chirps, preceded or followed by two tones. The songs of the Rufous-sided towhee, the Green-tailed towhee, and Orange-crowned warbler, are all variations on a theme.

The group continues down the trail as the bright line of sunlight engulfs them. The celebrity bird of the afternoon are many Lazuli buntings. On the western brightly lit slopes, perching on a Gambel’s oak, several of these buntings are seen. They males are aflame in their cloaks of brilliant iridescent blue. Bryant notes that a bird’s coloring are the result of their feathers refracting sunlight. The explains why colorful birds have dulled colors in diffused light, but radiant colors in full sun. Near trail mile 0.5, a Black-chinned hummingbird (Archilochus alexandri) sits on a powerline and obligingly ignores the birders as they take photographs. In the last third of trail mile, the sun and temperature has risen, the birds are less active, and the group quickly exits back to the road. A mallard rests in the flood retention pond.

I point out the cliff nest site that I followed last spring near mile 1.0 (Dec. 9th, 40°48.227 N, 111°52.204 W), but only about one-half of the group can see the nest. I had previously thought it was built by Peregrine falcons or Cooper’s hawks, but Bryant notes I am mistaken. Peregrines and Cooper’s hawks do not build stick nests, he says, a point supported in literature (Utah Legacy Raptor 2011). A later search on the internet returns many photographs of peregrines nesting in nearly identical stick nests. A probably resolution of the difference is found elsewhere: peregrine falcons sometimes will take over the stick nests of other raptors like eagles (White et al 2002).

Comparing the group’s Cornell Ornithology Lab birding logs for the canyon since April 30th reveals the arrival of many small migratory song birds with the abrupt rise in temperatures and the arrival of the vernal season (April 29th and May 1st). Common canyon birds in their logs in April through May 6th include mallards, European starlings, American robins, House finches, Song sparrows, Dark-eyed Juncos, Black-billed magpies, Mourning doves, Ravens, American crows, Red-tailed hawks, and Cooper’s hawks. New spring heat-seeking migrants that arrived just as the temperature switch tripped two or three days ago include the Peregrine falcons, Plumbeous vireo (Vireo plumbeus), Warbling vireo (Vireo gilvus), Orange-crowned warbler, Yellow warbler, Virginia’s warbler, Chipping sparrow (Spizella passerina), Green-tailed towhee, the Western tanager (Piranga ludoviciana), Broad-tailed hummingbird (Archilochus alexandri), Black-chinned hummingbird, Lazuli bunting, the Lesser Goldfinch (Spinus psaltria). These new colorful arrivals have followed the north running heat wave from the southern states and Mexico for a thousand miles to this northern canyon, and now that they have arrived, their next tasks will be mating and beginning the construction of nests.

I ask a question about what some of the most common canyon birds eat. I am interested in not only the simple phenological list of what bird species arrives when (this is what Thoreau did), but also how the web of insects, plants, and birds link together. The aviary experts’ answers are general and unsatisfying. “Seeds” (there are none), “grass” (they have not developed grains), and “insects” (there are still few, given the newly higher temperatures). The same vague discussions are found in my various paper and internet birding guides. I have witnessed a few instances in which canyon birds actually eating something over an entire year. A scrub jay ate acorns in the fall (Oct. 6th); wild turkeys ate winter acorns (Dec. 29th); chickadees ate winter fruit; spring kingfishers fish along the ponds and stream, although I have never seen them catch anything (March 19, April 6, 11, and 18); in the mallards eat spring algae from the stream; hummingbirds and dragonflies feasted on summer gnats (August 1st and August 11th), and a few days later, cliff swallows gorged on the dragonflies (August 22nd). In the spring of 2015, two falcons ate a mouse. But what are they, in particular the new arrivals, eating now? After this morning with the soundscape wizards and a subsequent literature search, I am struck both about how much science knows about the birds and how little science knows about birds. All things cannot be known, and I suspect there is little grant money available to fully construct and quantify the ecological relationships of even close natural areas, since minerals, logs, and skiers only have economic value and iridescent sheen of the Lazuli buntings do not.

A lone mallard sleeps near the shore of the flood retention pond. Jogging out of the canyon, the social-cause, 5k fun-run has begun, and three or four-hundred joggers are going towards milepost 0.5, along the opposite western leg along Bonneville Drive. A loudspeaker blares out popular music. Groups of racing bicyclists stopped by the police to allow the race to pass joke about blindly coming around a curve into such a mass of humanity. Their focus on life is different from mine, and neither, as they go about their respective enjoyment of the canyon, will perceive the dazzling blue of the Lazuli buntings seen by the wizards of the canyon soundscape.

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Iridescence in birds is caused by both pigments and the refracting structure of their feathers (Doucet and Meadows 2009; Rajchard 2009), and many birds also perceive light, including the iridescent refraction, in the ultra-violet spectrum (id). The view that humans see of birds is not what they see of each other. The blue feathers of birds, like the Lazuli bunting, may be hint that a bird can see ultra-violet light (see Doucet and Meadows, S118). Falcons use the ultra-violet reflection of mole and mouse urine to determine the density of their mammalian prey in fields (Rajchard). Fruit seeking birds like crows better see mature fruits because the ripe fruit better reflect ultra-violet light (id). Blue tits switch to the ultra-violet spectrum to see insects against non-contrasting backgrounds (id). The iridescent patches also help birds to distinguish their sexes, just as human birders do, but in some birds, the ultra-violet spectrum of their iridescent patches enhance the sex difference of their pigments seen in the human visual spectrum (id). Another study suggests that in the ultra-violet spectrum, some birds find it easier to distinguish eggs (id). Iridescence can also be an indicator of fitness to breed. Male birds lose iridescence as they age and when they are sick (Doucet and Meadows, S120-S121).

The iridescent patches of birds involve a trade-off. Iridescent patches, like those of the front-chin of the Broad-tailed Hummingbird and the side-neck of the Black-chinned hummingbird seen today, may be more visible to their predators, but they are also more visible to their potential mates (Doucet and Meadows). To reduce the predation cost of these patches, some patches are directional. A bird living in a diffusely, dark lit forest can perch in a ray of sunlight and send a narrow beam “flash” to other members of its own species and to potential mates (id). Predators circling above will not see this visual chatter. Conversely, the bright Lazuli bunting simply shines like a beacon. What do the hawks and falcons circling above see of these beautiful song birds in the shorter-bands of light that we human birders are unaware of?

* * * *

On May 6th, 1899, work to replace the City Creek water main with a larger diameter pipe was underway (Salt Lake Herald), although a suit seeking an injunction against the construction had been filed. On May 6th, 1888, Z. Jacobs canvassed citizens for suggestions on how to increase the city’s water supply, including Fire Chief Ottinger (Salt Lake Herald). Jacobs argued against building a dam in City Creek Canyon, since failure of the dam would destroy the downtown (id).

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