City Creek Nature Notes – Salt Lake City

May 22, 2017

May 22nd (Revised)

Continental Scale Bird Population Trends – Part I

(Science Section Revised May 28th.)

1:30 p.m. It will be a good day. As I ready to leave for the canyon and before even starting the car, a brilliant red House finch lands on a nearby telephone wire and sings happily for five minutes. Bright sunlight floods the canyon, and spring life explodes. There is too much to see, and I am overwhelmed. The roadside heats up with smells of fresh growth, and it mixes with the crisp cool air that rises from the transparent, chilled water of the swift stream. In the first mile, fifty birds are active, all singing in cacophony. The red ozier dogwood bushes are covered with small one-half inch bees with yellow and black abdomens and similarly miniature wasps with black and white striped abdomens. The first Western Yellowjacket wasp of the season lands. Nine Yellow swallowtail butterflies line the first mile with Mourning cloak, White cabbage, Painted Lady, and Spring Azure butterflies. Two Blue-eyed darner dragonflies fly above the road, and one unceremoniously defecates as it passes.

Immediately past Guardhouse Gate, three Warbling vireos exchange calls from the surrounding trees. Along the road to mile 0.3, I can distinguish about fifteen bird songs and calls, but by sound, I can identify the American robin, a Mountain chickadee, the Black-headed grosbeak, and the Song sparrow. A small Blue-gray gnatcatcher (Polioptilidae Polioptila caerulea) jumps parallel to the road along oak branches. Black-chinned hummingbird wings beat loudly.

At the bend in the road above picnic site 3, there is another riot of bird songs in a small cluster. Songs of the House finch, Mountain chickadee and others blend together. Then a blazing Yellow warbler comes of the screen of trees and lands in a nearby branch. The warbler leaves and finally, a Western scrub jay lands on a another branch. I play a recording of one of its kind squawking, the blue shouldered bird replies. This way we have an odd conversation. There is more, but this is enough.

This is the green explosion that the vernal season (February 16th) has been building to since the first of May.

* * * *

Parrish, Norvell and Howe’s Utah bird study covers one state – Utah (Parrish et al. 2007; Novell, Howe and Parrish 2005), but birds are international travellers. Olsen’s Pacific Flyway data is international but regional (Olsen 2017). Because of their dispersal, bird trends also need analysis on the continental scale. In 1966 in response to DDT’s impact on birds, the U.S.G.S. and the Canadian Wildlife Service began the first North American continental Breeding Bird Survey (BBS). However, design of the BBS did not cover weighted areas of differing habitat types (Bart 2005; Parrish et al. 2007 at 11). All survey sites were along roads, and this introduced a bias that would not allow for the study of how changes in habitat affects bird populations (id). Acknowledgement of the need to have coordinated continental scale non-game, longitudinal bird population data led to the establishment of the Partner-in-Fight Working Group (Bart 2005) to supplement the Breeding Bird Survey, and Parrish, Norvell and Howe’s work on Utah riparian habitats was part of the Partners’ system. Governmental agencies, including Utah, consolidate results into the national Breeding Bird Survey database (Sauer 2017; Pardieck 2016). Both the BBS and the Partners-in-Flight programs focus on professionally trained biologists working for or associated with many governmental agencies collecting high quality data by conducting transect surveys over time at the same sites.

Through 2015, the Breeding Bird Survey shows a declining population at 1.4 percent per year in its Western region (Sauer 2017). Plumbeous vireos decline at 2.3 percent per year.

Since the 1990s, concerns grew over what impact climate warming might have on bird populations and a need was perceived to develop management tools to early identify adversely effected bird species, and a management tool, the Partners-in-Flight the Conservation Concern Index was develop to provide guidance under the conditions of uncertainty in estimating local and global bird populations and their trends. The Partners-in-Flight methodology rates stresses on bird populations for 1,154 bird North American bird species (Panjabi et al 2012) based on five non-dimensional, ascending scales ranging from 1 (least concern) to 5 (most concern). The five indices are global population size, breeding geographical distribution, non-breeding geographical distribution, threats to surviving the summer breeding season, threats to surviving the non-breeding season, and population trends, and the combined indices yield a maximum total score of at most 25 denoted as the “Conservation Concern Index”.

Of the five indices, the global breeding population size is the most sensitive. It varies by a geometric growth rate of 10 denoted by a logarithmic index:

5 – World breeding population is less than 50,000 or 5 x 10^4.

4 – World breeding population greater or equal to 50,000 (5 x 10^4) and is less than 500,000 (5 x 10^5).

3 – World breeding population greater or equal to 500,000 (5 x 10^5) and is less than 5,000,000 (5 x 10^6).

2 – World breeding population greater or equal to 5,000,000 (5 x 10^6) and is less than 50,000,000 (5 x 10^7).

1 – World breeding population greater or equal to 500,000,000 (5 x 10^8) (Panjabi et al 2012).

The global breeding distribution index is the second most sensitive. It varies by a geometric growth rate of 3 denoted by a logarithmic index. An index of “5”, or highest concern, corresponds to 80,000 square kilometers or a U.S. state size of about 300 kilometers square. A breeding distribution index of “1”, or least concern, corresponds to 4,000,000 square kilometers, or a continent-sized 2,000 kilometer square(Panjabi et al 2012).

The Populations growth index is the least sensitive. An annual growth decline rate between 0 and 15 percent is rated “3”. Only crashing populations with a growth rate of greater than 50 percent are have an index of “5”.

Logarithmic risk indices are intended to overcome human compression bias, i.e. – our tendency to misinterpret risk over a large range of outcomes (Adams and Smith). Humans overestimate the risk of rare events, like botulism, and under estimate the risk of common events, like heart attack (id) and many natural processes, for example from our hearing and sight, increase sensitivity by a geometric scale. Thus, a logarithm index is a useful abstraction, but it is still often misperceived. If a risk level is expressed in terms of raw data, e.g. a world population breeding size of 50,000 to 500,000,000, this lends to unwarranted accusations of overstating for conservation. Conversely, when confronted with a logarithmic index, the natural human tendency is to erroneously interpret risk as an arithmetic sum. The earthquake Richter scale is a useful, common analogy. An earthquake of 5.0 on the Richter scale will shake the picture frames on your walls, but an earthquake of 7.5, will turn your home into a pile of sticks. The effects are perceived as additive, but in reality the effects are exponential.

To supplement the governmental North American Breeding Bird Survey by applying the Panjabi et al criteria on a global scale, private groups and industry from the North American Bird Conservation Initiative (NABCI). NABCI analyses are reported in annual glossy “North American State of the Bird” reports, – e.g. North American Bird Conservation Initiative (2009) and North American Bird Conservation Initiative (2016a). Another useful form of the their results is the annual NABCI Assessment Database, a spreadsheet that allows the user to sort and select birds by risk and habitat North American Bird Conservation Initiative (2016b). The mean of the index is 11.5, and a Conservation Concern Index higher than 13.5 suggests a high level of concern for which further study and action should be taken. A Conservation Concern Index (CCI) of 8.5 to 13.5 denotes moderate concern. This continental scale study provides insights into future threats that might change the currently stable bird diversity and populations totals seen in the canyon. But again, the CCI is a management tool and it does not report additive risk. Because its two key component scales, global breeding size and global breeding area, are logarithmic, the CCI scale conveys an expert opinion of a geometrically or exponentially increasing risk.

Two spring species that are regularly seen in the canyon (May 6th, May 20th) have CCI’s of 13 at the borderline of high concern: Virginia’s warbler and Plumbeous vireo. Others in the moderate concern category and their concern indices are: Broad-tailed Hummingbird (12), Steller’s Jay (11), Dusky Flycatcher (10), American Dipper (10), Black-chinned Hummingbird (10), Mountain Chickadee (10), Townsend’s Solitaire (10), Lazuli Bunting (9), Northwestern Crow (9), Orange-crowned Warbler (9), Western Scrub-Jay (9), and the Western Tanager (9). One commonality between these 13 species of 149 known to visit the canyon are that their non-breeding season ranges are in the southern Mexican highlands or the Pacific Coast lowlands. In short, land development in distant places might reduce their annual appearance in the canyon. But these results should be read in context. The NABCI indices for species found in the canyon generally indicate there is low concern of immediate threats to most species. The diversity of bird species in the canyon is stable. The NABCI “State of Birds” reports are not a trend-based forecast, although their short annual narrative report incorporates conclusions from Christmas Bird Count trend studies by the Audubon Society and governmental Breeding Bird Surveys.

* * * *

On May 22nd, 1914, the newly completed scenic automobile drive up City Creek and along 11th Avenue to be called Wasatch Boulevard will be opened to the public (Salt Lake Tribune). Other park improvements include the new Thirteenth Street Reservoir Park and adding lawn areas to Liberty Park (id).

May 20, 2017

May 20th

Spring Bird List

3:30 p.m. In the morning I am woken by the cawing of an American crow (Corvus brachyrhynchos) standing outside my window, but then I drift back off to sleep. Around noon, neighbors are buzzing over their photographs of a common Red fox (Vuplus vulpes) hunting mice in the city cemetery about one-third of a mile from my home and on the south-City side of the east-south canyon ridgeline.

In the afternoon, the cold snap of the last few days has ended and the canyon is again warming into the sixties under blue, ideal spring skies. Driving into the canyon along Bonneville Drive, the grasses have reached up to three feet high, but in the canyon they remain between one foot to eighteen inches in height. Along Bonneville Drive, young Curly dock plants rise, but there are none in the fields at mile 1.5. Arrowleaf balsamroot has noticeably disappeared from the surrounding hillsides through mile 1.5, and its yellow color has been replaced by the duller yellow of fields of Dyer’s woad. Along the first mile, where a few days ago there was a single Sticky Wild Geranium, there are now ten, and four blue penstemons are blooming. The other major blossom are the white inflorescences of chokecherry bushes or trees. Blue is the color of canyon near the stream, but at the Pleasant Valley lower field, I scan the surrounding hillsides for a hint of Arrowleaf balsamroot. There is none, only the green of the balsamroot’s wide bases surrounded by wide swaths of Dyer’s woad. A pattern repeats in the many sun-exposed small gullies that lead to the western salient’s ridgeline and below the eastern salient’s cliffs: Groves of green Gambel’s oak or Red Maple fill the damp soil or seeps along side canyon gullies, but where the side canyons begin to flare out, the dryer soils, formerly covered with balsamroot, are now covered in Dyer’s woad. At lower elevations along the western slope above the Pipeline Trail and above Bonneville Drive, some balsamroots remain in bloom, but their numbers are rapidly dwindling from their shriveling flowers.

Butterflies are recovering in the rising heat. Yesterday’s Western tiger swallowtail and Desert Elfin butterflies are joined by a few Spring Azure and White cabbage butterflies. About eight new, small and black unidentified butterflies appear. They move too fast to see any detail. Two examples of a new unidentified small black spider are on the road, and a small black ant is carrying a whole insect pupae, about eight times it size, back to its underground ant lair. Common houseflies are active on the road, and a larger Blue-eyed darner dragonfly patrols up and down the road. Along the Pipeline Trail, I flush out two Mormon crickets. Instead of red underwings (May 8th), they now flash muted orange underwings.

Where the chokecherry bushes are warmed by the sunlight, they are the buffet for the insects. The best of these is along the Pipeline Trail near mile 0.9, and the chokecherry bush is covered in about seventy bees, flies and a American Lady butterfly. The bush sits near a seep in a bend in the trail. It is in a large-tree shaded area, but a single shaft of light penetrates and warms the bush and its nearby air to fifteen degrees more than its surroundings. Another shaded chokecherry bush about fifteen feet away is ignored by these flighted insects. On the chokecherry inflorescences there are also two types of flies, one large and one small, and three types of bees, including a red-rumped worker bumble bee, wild common honey bee (Apis var.) and one of two Utah varieties of the Carpenter bee (Xylocopa californica) (Hodgson and Trina 2008). Near this seep, a tiny unidentified slug, about 1 centimeters by 3 millimeters in diameter crawls up the trail, and I help to the mud next to the seep. Three other chokecherry bushes fifty yards up from Guardhouse Gate and a full chokecherry tree at picnic site 4 are similarly covered, but to a lesser degree. These are also sunbathed.

A flock of four distant raptors circle and glide up canyon. Birds along the first 1.5 miles of road can be divided roughly into seven neighborhoods or groups: at Guardhouse Gate, at road mile 0.4, at road mile 1.0, the lower half of Pleasant Valley, mile 1.1 to 0.9 of the Pipeline Trail, the Trail between mile 0.9 and 0.5, and the Trail between mile 0.5 back to the Gate. There are more calls than yesterday, with between 5 to 10 birds in each neighborhood. By sound alone, I can pick up a few of the easiest out of a chorus of ten different songs: the Lazuli Bunting at the Gate; a Song sparrow and an American Robin near mile 0.5; a near road mile 1.0,; and a Black-chinned hummingbird flying near Trail mile 1.0. I have gathered recordings of about 40 spring birds on my smart telephone, and have begun to replay them constantly in the hopes of building a beginner’s skill for distinguishing their songs. The avian soundscape is being to make more sense to my untrained ear.

As I reach Guardhouse Gate, there is a young woman standing 50 feet from the road, half obscured by blinds made leafed branches of Gambel’s oak, and she is singing gospel and folk songs in a loud but beautiful voice. She has long-black hair, is wearing a short, summer dress of yellow printed ethnic cotton, and is illuminated by that special warm light before dusk. Several strolling couples and myself discreetly walk up to the side of the road for an impromptu concert. For a moment, my mind is momentarily transported back to my adolescence and a similar scene from 1971. After a few minutes, everyone wanders away, leaving her to practice her singing without disturbance, but grateful for a unique moment.

* * * *

The slate of spring canyon birds for this year has sufficiently filled out that a list is timely. The 54 species represented shows the diversity of bird life that is finding living niches in the canyon and making connections between its plants and insects.

List of Spring Birds in City Creek Canyon March through May, 2017 by Order and-or Family (N=54)

Orders Accipitriformes and Falconiformes – Hawks, Eagles and Falcons – Birds that Hunt Other Birds

• Bald Eagle (immature) (Haliaeetus leucocephalus).*

• Cooper’s Hawk (Accipiter cooperii).

• Golden Eagle (Aquila chrysaetos).

• Northern Goshawk (Accipiter gentilis).

• Peregrine Falcon (Falco peregrinus).

• Red-tailed Hawk (Buteo jamaicensis).

• Sharp-Shinned Hawk (Accipiter striatus).

Order Anatidae – Ducks

• Mallard (Anas platyrhynchos).

Order Apodiformes – Swifts and Hummingbirds

• Black-chinned Hummingbird (Archilocus alexandri).

Order Galliformes – Pheasants and Guineafowl

• California Quail (Callipepla californica).

• Chukar (Alectoris chukar).

• Wild Turkey (Meleagris gallopavo).

Orders Piciformes and Coraciiformes – Woodpeckers and Kingfishers

• Belted Kingfisher (Ceryle alcyon).

• Downy Woodpecker (Picoides pubescens).

• Northern Flicker (Colaptes auratus).

Order Strigiformes – Owls

• Western Screech-Owl (Otus kennicottii).*

Order Passeriformes – Larger Perching Birds

Family Corvidae – Crows, Jays and Magpies

• American Crow (Corvus brachyrhynchos).

• Black-billed Magpie (Pica pica)

• Common Raven (Corvus corax).

• Steller’s Jay (Cyanocitta stelleri).*

• Western Scrub-Jay (Aphelocoma californica).

Order Passeriformes – Mid-sized and Smaller Perching Birds

Family Cardinalidae – Cardinals and Grosbeaks

• Black-headed Grosbeak (Pheucticus melanocephalus).

• Lazuli Bunting (Passerina amoena).

• Western Tanager (Piranga ludoviciana).

Family Columbidae – Pigeons and Doves

• Eurasian-collared Dove (Streptopelia decaocto) (invasive).

• Mourning Dove (Zenaida macroura).

Family Emberizidae – Sparrows and Buntings

• Chipping Sparrow (Spizella passerina).

• Dark-eyed Junco, Slate type (Junco hyemalis).*

• Green-tailed Towhee (Pipilo chlorurus).

• House Sparrow aka European Sparrow (Passer domesticus) (invasive).

• Rufous-sided Towhee (Pipilo erythrophthalmus).

• Song Sparrow (Melospiza melodia).

• Spotted Towhee (Pipilo maculatus).

Family Fringillidae – Finches

• House Finch (Carpodacus mexicanus).

• Lesser Goldfinch (Carduelis psaltria).

Family Hirundinidae – Swallows

• Bank Swallow (Riparia riparia).

• Cliff Swallow (Petrochelidon pyrrhonota).

• Northern Rough-winged Swallow (Stelgidopteryx serripennis).

• Violet-green Swallow (Tachycineta thalassina).

Family Paridae – Chickadees

• Black-capped Chickadee (Poecile atricapillus).

• Mountain Chickadee (Poecile gambeli).

Family Parulidae – Wood-Warblers

• Orange-crowned Warbler (Oreothylpis celata).

• Virginia’s Warbler (Oreothylpis virginiae).

• Yellow Warbler (Dendroica petechia).

Family Turdidae – Thrushes

• American Robin (Turdus migratorius).

• Townsend’s Solitaire (Myadestes townsendi).

Family Tyrannidae – Tyrant Flycatchers

• Dusky Flycatcher (Empidonax oberholseri).

• Olive-sided Flycatcher (Contopus cooperi).

Family Vireonidae – Vireos

• Plumbeous Vireo (Vireo plumbeus).

• Warbling Vireo (Vireo gilvus).

Family – Other with Family Name

• Blue-gray Gnatcatcher (Polioptilidae Polioptila caerulea).

• European Starling (Sturnidae Sturnus vulgaris) (invasive).

• Red-breasted Nuthatch (Sittidae Sitta canadensis).

• Ruby-crowned Kinglet (Regulidae Regulus calendula).

Sources: Cornell Lab. 2017 Ebird Observation Lists by Bryant Olsen with Joshua Hunt; Author’s Observations. * – Author only sighting claimed.

* * * *

The Wasatch Front Mountain Range has not seen a decline in the number of avian species since the Euroamerican arrival, but no opinion is expressed on any decline in the population of these birds. As noted before (March 4th), ornithologist Robert Ridgeway conducted a survey of birds in Parley’s Park at the summit of Parley’s canyon about ten miles from City Creek Canyon between June 23rd and August 16th, 1869 (Rawley, 69-79). He found 116 bird species. Comparing Ridgeway’s list with Cornell Ornithology Laboratory’s Ebird List for City Creek Canyon for 1900 through 2017 shows 149 species (Cornell Ornithology Lab. 2016, Cornell Ornithology Lab. 2017). For the years 2000 to 2017, 147 species are listed, and for 2012 to 2017, Cornell totals 143 species (id). There are some minor non-duplicates between the historical and modern lists. The Yellow-bellied sapsucker is not currently found in City Creek, and the range of other birds has changed. Birds such as sandpipers and Sandhill Cranes do not presently frequent City Creek but can still be found at the Great Salt Lake’s beaches and marshes. But essentially, the avian diversity of Ridgeway’s 1869 mountain birds is still intact at City Creek Canyon after 148 years.

That the diversity of Utah’s many migrant birds is stable is also shown by Parrish, Norvell, and Howe of the Utah Division of Wildlife Resources in a multi-year study from 1992 to 2005 (Parrish et al. 2007; Norvell, Howe and Parrish 2005). Examining 202 statewide bird species over 12 years at 37 Utah sites, Parrish and colleagues found no significant trend in mean annual species richness (id, p. 27, Fig. 4).

* * * *

On May 20th, 2014, Salt Lake Fire Captain Scott Winkler reports that the City has spent $650,000 on six new firetrucks specialized from fighting fires in grass brush areas around luxury homes near Ensign Peak and in City Creek Canyon (Deseret News). On May 20th, 1903, the City Council and Mayor considered issue bonds to construct reservoirs including a 5,000,000 gallon reservoir at Pleasant Valley (Salt Lake Telegram). On May 20th, 1901, an estimated three-hundred people went up City Creek Canyon, one-thousand to Liberty Park, and three-hundred for recreation (Salt Lake Tribune). On May 20, 1896, the City council considered moving the responsibility for maintaining City Creek watershed protection to the health department and the duties of the City Creek Canyon patrolman were described (Salt Lake Tribune). There were five full-time patrolmen. Three men are employed at the lower Brick Tanks keeping the screens clear of debris. Two men are employed for 12 hours per day to service the upper high-line tank screens and to patrol the upper canyon to prevent sheep grazing. Two other men service the Twentieth ward tank and the Capitol Hill Reservoir (id). City Creek has been rip-rapped for two miles above the lower Brick Tanks. On May 20th, 1896, high spring run-off has turned City Creek into muddy water and the water is clearing (Salt Lake Herald).

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).

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?

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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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