City Creek Nature Notes – Salt Lake City

June 23, 2017

June 21st

Growth Spurts

6:45 p.m. In the cool of the late evening, I jog towards Pleasant Valley at mile 1.2. A Lazuli bunting (Passerina amoena) perches near the gate. Near mile 0.3, a flash of bright yellow on the outside of a tree catches the eye. It is a Yellow warbler (Dendroica petechia). At mile 1.1, I mistake plaintive calls for raptor chicks, but it is only the squawking of a pair of Western scrub jays (Aphelocoma californica).

The summer-like heat turns flowering plants. The leaves of Wild carrots (Lomatium dissectum), a.k.a. Fernleaf biscuitroot, are browning, and their seeds are turning a light purple. Curly dock weeds (Rumex crispus) have turned a deep brown. I admire Curly dock. It grows, flowers, and dies over only for a few weeks in the spring, but then its rich brown color accents the canyon throughout the rest of the year. Only in the early spring, does it finally succumb to winter’s weather, and then in a few weeks, it begins to regrow. Even the seeds of yesterday’s Milkweed have turned from a light green to a subtle purple in a single day. Foxglove beardtongues (Penstemon digitalis) that have delicate bell-like flowers have deepened in color from white to streaked pink.

Other plants respond to this initial summer heat with a growth spurt. Starry solomon’s seal plants (Maianthemum stellatum) have reached almost two feet in height. At the seep below picnic site 6, watercress (Nasturtium officinale) has grown four inches in height in just a few days. Scouring rush horsetails (Equisetum hyemale) along the road stand erect and have also reached two feet in height. At lower Pleasant Valley field, Wild bunchgrass (Poa secunda) is two to two and one-half feet high. Heat drives this rush.

Hovering other the Pleasant Valley field, a fleet of twenty Common whitetail dragonflies dart back and forth and play tag in the evening breeze. Their miniature relatives, Circumpolar Bluets (Enallagma cyanigerum) line the first mile roadside. Returning down-canyon, a Pinacate stink bug (Eleodes sp.), a.k.a. the Darkling sting bug, is running down the road. This is the first time that I have seen one fast motion, and usually they standing with their abdomens pointed into the air and ready to launch a chemical spray on predators. When running, its oversized rear legs make its large black abdomen comically waive back and forth. Since cars are banned from the canyon today, many bicyclists streak by heeding on caution for speed.

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Per Thoreau’s “Journal” on June 21st, 1852, he notes that adder’s tongue, a fern, smells like snakes. He hears a cherry bird. He sees a field with snap-dragon and he notes that lupines have lost their blooms. He hears thunder when there are no clouds in the sky. He collects morning glories. On June 21st, 1854, he notes the many smells in the air, including may-flowers and cherry bark. He compares how a stream bank has grown from a low covering of brown in spring to a thicket of weeds in summer. He finds a small pond with two pout fish and a brood of small fry. He describes a sprout forest – a forest of small sprouts that grows from fallen trees. He sees wild roses. On June 21st, 1856, he sees night hawks, and on June 21st, 1860, he observes pine pollen covering the surface of water.

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On June 21st, 2000, Mayor Rocky Anderson held a press conference urging Congress to pass a bill that would designate a portion of offshore federal oil revenues to fund improvements in local parks like City Creek Canyon (Salt Lake Tribune). On June 21st, 1995, Rotary Club members repainted benches at Rotary Park in City Creek Canyon (Salt Lake Tribune). On June 21st, 1994, a 19 year-old man was robbed at knife point by his passenger after they drove to City Creek Canyon (Salt Lake Tribune). On June 21st, 1934, Street Commissioner Harold B. Lee referred a proposal by former City Engineer S. Q. Cannon to employ road crews to widen City Creek Canyon Road to the Depression Federal Emergency Recovery Act Bureau (Salt Lake Telegram). On June 21st, 1912, City Parks Commissioner George D. Keyser proposed a circular scenic boulevard be created up City Creek, along 11th Avenue to Fort Douglas, then to Sugarhouse, and then returning to the City’s center (Salt Lake Tribune, Salt Lake Telegram). The route would be lined with trees (id). On June 21st, 1906, City Engineer Kelsey reported that 100 miles of sidewalks will be completed in the City this year and another 25 miles of roads will be paved or graveled (Salt Lake Telegram). A minor $1,000 project will construct a bridge in City Creek Canyon (id).

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.

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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).

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