City Creek Nature Notes – Salt Lake City

May 25, 2017

May 23rd

Continental Scale Bird Population Trends – Part II

3 p.m. Unwittingly, I disrupt the community of birds just north of Guardhouse Gate. It is another warm, clear day, and I plan to spend this afternoon’s run developing my novice song bid, soundscape skills (May 6th). Over the weekend, I have assembled recordings of about forty-five birds from the Cornell Laboratory observing lists (May 20th), and they have been transferred to my telephone. The songs are sorted in order of similarity. Thus, I hope to learn the songs by listening to them throughout my day and by replaying the recording to identify unseen birds from their sounds alone. But this is not an easy skill to acquire. Some birds caw, others have warbling songs, and still others have four or five beat calls. The variations are endless: some warbling songs end on a high note, others on a low, some are long, others are longer. Call-like songs begin on a low-note, followed by a three or six beat high tone; others begin on a high-note, followed by a five count low-note. Others have a rapid trill. Nor is there much organization by either genus of bird or its outward appearance. The Black-headed grosbeak has song similar to the smaller Song sparrow, but the Rufous-sided towhee, which looks very similar to Black-headed grosbeak, has a two-beat call followed by a rapid, machine gun trill. The Lazuli bunting, which has a seed-crushing mouth sounds like the grosbreak and towhee, has a song that is a deeper throated version of the smaller Warbling vireo which has a mouth shaped for catching insects. Conversely, similarity of form can imply similarity of call. Some of the most colorful songbirds in the canyon are insectivores. The Warbling vireo, the Yellow warbler, and the Virginia’s warbler are similar in form and have variations on the same song, like some avian version of humanity’s proto-Indo-European language, but they do not all share the same family in the binomial nomenclature system. The Song Sparrow and House Sparrow are similar in form and voice tone, but their songs are very dissimilar.

Song birds along the first mile can be roughly divided into four communities: there is cluster between the Gate and mile 0.1 and picnic site 1 along both sides of the stream. A second group collects around the bend above picnic site 3 on the east side of the stream. A third is in a hollow below picnic site 5 on the west side, and a fourth along the western oak-covered slope near mile 1.0. These cluster at every 0.2-0.3 miles are connected by loose strings of individual avians. To these four neighborhoods, a five lays to the west of and along the Pipeline trail where the Gambel oak forest gives way to open grass and brush lands. The predators – Peregrine falcons, Red-tailed hawks, Cooper’s hawks, and American kestrels (Falco sparverius) – form their own neighborhood hovering in the sky over the song birds.

I begin at the first group near mile 0.1, where yesterday there was a riot activity. Since today, it is later in the afternoon, things are more subdued, but I can still distinguish six or seven different, unseen bird voices. Initially, I struggle with making any identification, and I become absorbed in loudly replaying about ten songs that represent the voices at mile 0.1. I listen to one song, and then try playing the two or three best candidate recordings to select the best match. After five minutes, I look up, and three birds have come out of the nearby screen of green. A Lazuli bunting perches on the top branch of a thirty foot Box Elder tree. On a nearby Gambel’s oak, a female House finch perches and stares. Across the road in the Box Elder, there is a bright flash of red and yellow midway down the tree. It is a male Western tanager in full breeding plumage, and I start replay a recording of his species in order to keep his attention. For the two months of its breeding season, the head of the tanager turns a brilliant red, and this contrasts with its vivid yellow underplumage and black back. This male has caught the lengthening rays of afternoon sunlight that is softened by moisture in the air, and its red iridescent plumes blaze.

After working with the recordings for one-half hour, I am able to make rudimentary identifications by sound alone of the the Western tanager, a Lazuli bunting, a Warbling vireo, a Song sparrow, and American robin. What strikes me about this lower community is its heterogeneity. There are perhaps seven species all sharing the same one-quarter square mile. They cooperate in sharing the space. Birds are known to share the same forest space by specializing in different food niches, it is early in season and food may be plentiful, and territorial nest building may not have been completed.

Traveling up canyon, the bird community in the hollow near picnic site 5 is populated by only Warbling vireos. Further up canyon, a lone Spotted towhee caws and trills. American robins are dispersed along the first mile road.

Spring Azure butterflies have had a mini-R reproductive explosion. Usually there are three or four larger adults along the first mile road. Today, I count 20 smaller streaked blue versions only three-quarters of an inch in size. The next generation has hatched, and they play among newly cut grass. The City has come through the canyon, and as a fire prevention measure, it has mowed down the two and three foot grass around each picnic area. The air is sweet with cut-grass smell, and further back from the sickle’s cut, the green grass is interrupted by the first loud yellow of newly opened Toad flax (Linaria vulgaris), also called Butter and Eggs plant. This common roadside noxious weed has a beautiful, intensely yellow and orange, orchard like bloom.

Coming back down canyon close to six in the evening, these bird communities are silent, and only the evening town criers of the canyon, the House finches, repeat their their one-high, two low, call of three notes. Near mile 0.5, an immature Terrestrial gartersnake (Thamnophis elegans) crawls across the road. The garter eats insects, e.g. – the Stink bugs that rest along the roadside and snails (May 16th).

Incongruous to this serenity, a group of ten people walk up the road, and two have small caliber handguns strapped to their sides. These “open carry” gun rights advocates, whose right to openly carry guns is sanctioned by the state legislature, have no need for these weapons. Discharging them in the canyon below mile 0.4 violates city and county ordinances, and regardless of the legality, their attempt to drag society back into uncivility and barbarism of some imagined historical western landscape is uniformly disapproved of by the majority of members of the surrounding neighborhoods. Regularly, such displays or the discharge of firearms results in canyon walkers making worried telephone calls to the police, and the police do respond to hand out tickets. While I have some appreciation of how individualism and capitalism can drive people into a mindset that perpetually fears others, this group is not in any danger in the canyon this evening. No one is hiding in the bushes ready to rob them, and their flashy presence in the canyon is an unwelcome intrusion. Like the songbirds around them and the red blaze of the tanager, their weapons are an overstated claim for social attention and of personal territory.

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The National Audubon Society recently has become a leader in continental scale studies of populations and of future threat forecasting. In 2013, the National Audubon Society released their report titled “Developing a Management Model of the Effects of Future Climate Change on Species: A Tool for the Landscape Conservation Cooperatives” based on its Christmas Bird Count (discussed below) and BBS data (National Audubon Society, Schuetz, Distler, Langham, 2013). Coupled with global climate models, the Audubon’s Christmas Bird Count data allowed the Society to model changes in bird summer and winter ranges, summarized in national maps, based on varying degrees of global warming. In the Great Basin (and in the canyon), their model predicted increases in bird species richness during the winter season and declines in bird species richness during the summer season (id, 27-29, Figs. 2.8-2.9). In an updated study, Langham and colleagues from the Society used further advanced modelling techniques with respect to 588 North American continental birds, and they forecasted that by 2080 under a high-emissions high-warming scenario, about 53 percent of the 588 species would find that 50 percent of their current range, particularly for summer breeding, would become unsuitable (Langham et al. 2016).

With respect to continental-scale population trend studies, the Audubon Society’s annual Christmas Bird Count has collected bird counts since 1901. Unlike professional studies, the Christmas Bird Count (CBC) suffers from a number of inherent design controls. CBC bird identifications are made by error prone amateurs at differing locations and differing types of locations, e.g. – in the field or at feeders, between each annual sampling. Fluctations in the number of observers between years can introduce observation bias. Those characteristics limit the ability to use CBC data to predict trends in bird populations using traditional statistical techniques. Conversely, the CBC has been the collecting massive amounts of data from numerous amateurs around the country for more than a century. For example, in the 2016 count, over 56 million birds were manually counted. Increases in inexpensive computing power and application of advanced statistical techniques eventually allowed for the use of this citizen science data to make reasonably statistically confident statements of about trends in bird populations sampled from a wide variety of habitats. In particular, the mathematical techniques of multi-level regression, also called hierarchical modelling, allows for the extraction of bird density trends over time from the massive, but uncontrolled, data sources collected by the Audubon Society. Since 1990, habitat change from climate warming has become an important issue. Application of these analytic improvements also allow trends to be examined in the context of varying habitats, and thus, making the CBC data useful for exploring trends in habitat change from development and climate warming affects bird populations.

Soykan and colleagues with the National Audubon Society estimated North American continental populations of 551 North American bird species and for a subset of 228 species that do not frequent bird feeders using the Society’s annual Christmas Bird Count data (Soykan et al. 2016). They found that for all 551 species, 68 percent had increasing density trends from 1966 through 2013. Thus, 32 percent have a declining trend, a fact exploited in NACBI glosssy annual “State of Birds” reports. For the subset of 228 species, Soykan et al found an 0.9 percent growth trend across 1966 to 2013. They noted the geographically, declining species were concentrated at lower latitudes and increasing species were located at higher latitudes (id), and this suggests that generally, bird populations are shifting their ranges northward. For the future canyon, this is consistent with Schuetz, Distler and Langham’s 2013 modelling suggesting that warmer climates would increase winter species diversity in the Great Basin as birds move their ranges north (above).

Soykan et al’s supplemental data provides further insight into Utah trends (Soykan et al. 2016), but it also underscores the problems and differences of professional verses amateur data collection. Conflicting with the Parrish, Norvell and Howe declining Utah trends for 1992 to 2005, Sokyan and colleagues found from CBC counts for 1966 to 2013, an increasing bird population trend of 2.7 percent for Utah (Table S.4) and 2.8 percent for the Great Basin region (Table S6). Students of introductory statistics will recall the Rule of 70: the doubling time or halving time of a population can be estimated by dividing 70 by the annual rate. Thus, the CBC trend suggests that Utah bird populations will double in 25 years, while the Parrish, Norvell and Howe rate suggests populations would halve in 70 years.

Although overall, Soykan et al’s continental population trends derived from CBC counts were statistically similar to 228 professional BBS specie trends, for a small subset of 33 species, CBC and BBS trends significantly differed (Table S.9). Some of the differences involve species frequently seen in the spring canyon. For two species, Swainson’s Hawk and the Black-headed Grosbeak, the CBC found continental declines around 3 percent per year, while the BBS surveys found increases of less than 1 percent per year. A three percent decline suggests populations will halve in about 25 years. For eight other species found in the canyon, the CBC found a slight increasing population trend, while BBS found populations declining at more than 1 percent per year: Song Sparrow, American Kestrel, Belted Kingfisher, Mourning Dove, Orange-crowned Warbler, Yellow Warbler, Chipping Sparrow, and the Broad-tailed Hummingbird.

Again, overall bird population studies continue to indicate that currently and for the near future, bird specie diversity and bird populations should remain stable or have a slight decline, as indicated by the Parrish, Norvell and Howe studies (Parrish et al. 2007). Soykan et al and Langham et al conclude overall birds are moving their summer ranges northward and they are decreasing the area of the summer and winter ranges around the best habitats in response to a warming climate, and under that scenario, Utah bird populations would increase as birds move further north. But whether population trends will decline in a severe global warming occurs scenario, whether they will increase as more birds move their ranges north in response to southern latitude warming, or whether Utah bird populations will increase after the reversal of the current Intermountain drought phase of the Pacific Quasi-Decadal Oscillation (February 7th) remains to be seen. Continued monitoring, such as that occurring through professional and citizen science surveys, is the only means to have a definitive early warning of any dramatic change, for better or worse. Other unanticipated changes, both good and bad, may also occur.

These mathematical models of bird populations, as with proof of biophilia studies, provide only the most general of signs and no clear answers. Proof to a reasonable degree of scientific certainty cannot be found in the statistics of bird populations, and thus, we are forced to fall back on human values and human judgment in deciding what to and how to protect nature. But as with local weather and the Pacific Quasi-Decadal Oscillation, it is only by looking on a continental scale that over-arching patterns in nature can be seen. A local-only perspective, like Plato’s prisoners in his allegorical cave, can give us a limited, uninformed, and wrong view of the world.

There is a further brilliance to the CBC data and Schuetz, Distler and Langham’s 2013 study. They provide detailed ranged summer and winter maps for 36 bird species of concern (id, 114-181) on a continental scale and with previously unseen fidelity (Schuetz, Distler and Langham’s 2013). Presumably, such maps can be generated for all birds in the CBC study. Previously, bird summer and winter range maps were rendered with broad colored areas across a U.S. map with northern and summer range lines, e.g. – those seen in my old 1990 Peterson’s Western Birds guide or my favored, dog-earred 1966 Guide to Field Identification of North American Birds, illustrated by Arthur Singer. The ranges of migration were indicated by broad directional lines. By combining CBC bird observations with satellite habitat data, Schuetz et al render detailed core range maps.

* * * *

On May 23rd, 2012, Lowell Bodily, Salt Lake Valley Health Department, again reported on homeless tent camps in the valley, and he notes that some homeless camp along the Bonneville Shoreline Trail in and near City Creek Canyon (Salt Lake Tribune). On May 23rd, 2006, the Lion House reports that it hosts about 82,000 visitors per year (Salt Lake Tribune). (In the 1850s, the Lion House sat next to the tollgate that controlled access to City Creek Can yon.) On May 23rd, 2002, in a letter to editors of the Salt Lake Tribune, a Sandy resident decries how a new luxury home has defaced the beauty of Ensign Peak and City Creek Canyon (Salt Lake Tribune). On May 23rd, 1996, Anschutz Ranch East Pipeline Inc. proposes to build a crude oil pipeline from Park City that would cross through City Creek near the water treatment plant (Salt Lake Tribune, June, 24, 1996). On May 23rd, 1914, the Salt Lake Telegram published a photograph layout and description of driving the new scenic boulevard up City Creek, along 11th Avenue and down 1300 East (Salt Lake Telegram). On May 23rd, 1905, Land and Water Commission Ben D. Luce requested that the City council to ban automobiles from driving up City Creek Canyon due to the possibility that they will cause accidents by frightening horses (Salt Lake Herald).

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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.

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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 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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