City Creek Nature Notes – Salt Lake City

December 10, 2016

December 10th

Filed under: Birds, Nests — canopus56 @ 9:23 pm

A Census of Bird and Insect Nests

Seeing nests is not easy. Even though I made quick digital pictures of the nests and their locations, on successive days finding the same nest can be difficult. Sighting a nest depends heavily on lighting. Some nests are best seen when back lit; others are easier to find when they are illuminated face on from the front. They are also transient objects. The weather has worn the Bald-faced wasp at picnic site 9 down to one-third of its original size, and the largest hornet nest in the canyon was blown out of its tree around December 6th.

The list below consists of forty nests that were verified with global positioning system (GPS) coordinates. All have been observed on at least three separate days. GPS positions vary by ±0.010′ to ±0.040′ (minutes) between readings and depend on the number of satellites used to fix a position. With a modern cell phone, GPS coordinates can be accessed even when outside the cell phone tower network by installing many of the free GPS-mapping phone applications. I use the application “GSP Essentials” and its “Satellites” feature that shows current GPS coordinates. Readings taken below picnic site 3 have a wider variance and are less accurate because of the high-voltage power line that is strung overhead across the canyon distorts the GPS radio signal.

Snag nests are nest created when a woodpecker drills holes into dead tree trunks (a “snag”) and a hollow is excavated inside the trunk. Generally, snag nests occurs in dead trunks that are 10 to 14 inches in diameter. Nests that are easy to see are marked. The platform-type nests may be tree nests of squirrels. Squirrels sometimes take over and expand bird nests in trees and at other times they build their own. Possible squirrel nests are marked.

Removing almost any migratory bird nest is a felony punishable by up to two years of imprisonment and a $250,000 fine under the Migratory Bird Treaty of 1918, 16 U.S.C Secs. 703-712. For this reason, internet auction sites like eBay prohibit selling all bird nests. Since you cannot tell the difference between a controlled and uncontrolled nest, it is in your best interest to leave all nests alone.

List of Bird and Insect Nests Found in the First Two Miles of City Creek Canyon on December 1st-7th, 2016:
• 1 platform nest in 40 feet high, south side of the road at “Rough Pavement” sign. 40°47.547′ N, 111°52.618′ W. Possible squirrel nest.

• 1 hemisphere stick nest about 125 feet down canyon of picnic site 1, approximately mile 0.1, south side of the road. 40°47.589′ N, 111°52.599′ W. Possible squirrel nest.

• 1 Bald-faced hornet nest about 20 feet down canyon of picnic site 1 sign, south side of the road. 40°47.601′ N, 111°52.605′ W.

• 1 hummingbird type nest in the low dogwood bushes at the up canyon end of picnic site 1, south side of the road. The nest is in the bushes to the south of the “Share the Road” sign. This is best nest of this type. 40°47.606′ N, 111°52.586′ W. Easy to see. Please do not harvest this accessible nest.

• 1 hummingbird type nest in tree 30 feet up canyon of picnic site 1, south side of the road. Also 40°47.619′ N, 111°52.588′ W. Difficult to see. It is located among the dense branches of a river birch on the far side of the stream.

• 1 hummingbird type nest in tree 200 feet up canyon of picnic site 1, south side of the road. See August 27th. 40°47.636′ N, 111°52.577′ W. Easy to see.

• 1 hanging basket nest at picnic site 3, high in 80 feet tree, south side of the road. 40°47.811′ N, 111°52.464′ W.

• 1 basket circular nest 80 feet down canyon from picnic site 3, north side of the road. 40°47.784′ N, 111°52.742′ W.

• 1 possible circular twig nest at picnic site 3, north west side of the road. 40°47.848′ N, 111°52.440′ W.

• 1 possible circular twig nest at picnic site 3, south side of the road. 40°47.848′ N, 111°52.443′ W.

• 1 Bald-faced wasp nest at picnic site 4, north west side of the road. See December 1st. 40°47.866′ N, 111°52.421′ W. Easy to see.

• 1 grass-woven nest 100 feet down canyon of picnic site 5, south side of the road. Also at 40°47.953′ N, 111°52.407′ W. Gone December 7th. Probably fallen from tree.

• 1 Bald-faced wasp nest 200 feet up canyon of picnic site 5, south side of the road. 40°47.979′ N, 111°52.370′ W. Easy to see.

• 1 Bald-faced wasp nest 200 feet down canyon of picnic site 6 on the north side of the road, high in the upper branches of a 100 foot tall cottonwood tree. This nest is twice the size of a basketball. Unable to locate on December 6th after snow storms. Last seen December 4th. This nest probably was blown out of the tree. 40°48.061′ N, 111°52.339′ W.

• 1 basket nest 400 feet down canyon from picnic site 6, north side of the road. 40°48.033′ N, 111°52.359′ W.

• 1 hemisphere type twig nest 300 feet down canyon and around the bend from picnic site 6, south side of the road. 40°48.047′ N, 111°52.351′ W. Possible squirrel nest.

• 1 twig nest 400 feet down canyon from picnic site 6, north side of the road. 40°48.062′ N, 111°52.337′ W. Difficult to see. Is located in a branch thicket. Possible squirrel nest.

• 1 hanging basket nest 100 feet down canyon from picnic site 6, high in tree, north side of the road. 40°48.142′ N, 111°52.307′ W. Unable to locate on December 7th. Probably fallen from tree.

• 1 Paper wasp nest in the end of the hand-rail tube on the red bridge near mile 0.9. 40°48.180′ N, 111°52.281′ W. Easy to see. Look down the open tube ends.

• 1 Bald-faced Hornet nest 300 feet up canyon from red bridge, north side of the road. 40°48.208′ N, 111°51.219′ W. Easy to see.

• 1 Peregrine falcon nest in the north-west wall near mile 1.0, visible only from the Pipeline trail. 40°48.227 N, 111°52.204 W on pipeline trail. Look above the split in cliff face due west. Barely visible without binoculars. Easy with binoculars.

• 1 possible twig type nest 400 ft down canyon from picnic site 7, south side of the road. 40°48.240′ N, 111°52.219′ W.

• 1 small circular woven hummingbird type nest 125 ft down canyon from picnic site 7, south side of the road. 40°48.246′ N, 111°52.030′ W. Easy to see.

• 1 circular type twig nest up canyon from picnic site 7, south side of the road. 40°48.260′ N, 111°51.980′ W.

• 1 medium sized hanging basket type nest 100 feet up canyon of picnic site 7, south side of the road. Unable to locate on December 6th. May have been felled by snow storm since December 3rd.

• 1 small platform twig nest 300 feet down canyon and around the bend from picnic site 7, south side of the road low in a Gambel’s oak. 40°48.259′ N, 111°52.890′ W.

• 1 snag nest across the stream from picnic site 7 in a forty foot tall dead tree, south side of the road. 40°48.253′ N, 111°51.989′ W. Easy to see. Look at top of dead, white vertical trunk.

• 1 possible snag nest at the up canyon end of picnic site 7, south side of the road. Several small holes are drilled at the top of the snag. Also 40°48.253′ N, 111°51.989′ W.

• 1 snag nest across the stream from picnic site 7 in broken tree leaning towards south side of the road. 40°48.253′ N, 111°51.989′ W. Difficult to see. Entry hole is in the side of the trunk facing down canyon.

• 2 medium sized platform twig type nests 100 feet up canyon of picnic site 8, one on the south side of the road and a second on the north side. 1 basket circular nest high in south tree. 40°48.277′ N, 111°51.936′ W. Easy to see.

• 1 Bald-faced wasp nest at picnic site 9, south side of the road. See November 27th. 40°48.288′ N, 111°51.889′ W. Elevation 5051 feet. Easy to see.

• 1 Paper wasp nest at the pipeline gas safety value across from picnic site 10, north-west side of the road. The nest is inside the hanger for the gate. 40°48.317′ N, 111°51.784′ W. Easy to see.

• 1 small basket nest 100 feet up canyon from milepost sign 1.5, south side. 40°48.324′ N, 111°51.601 W. Easy to see.

• 1 small circular twig nest 250 feet up canyon from milepost sign 1.5, south side. 40°48.331′ N, 111°51.570′ W. Easy to see.

• 1 snag nest 300 feet up canyon from milepost 1.5 sign near “Service vehicle” sign. 40°48.334′ N, 111°51.540′ W. Difficult to see. The vertical white snag is hidden inside a copse of Gambel’s oaks.

• 1 grass woven hummingbird nest 200 feet up canyon from picnic site 12, south side. 10 feet high in a Gambel’s oak. 40°48.380′ N, 111°51.514′ W. Easy to see.

• 1 snag nest at the up canyon side of the old Pleasant Valley Reservior clearing, 150ft south west of the road on the trail. The snag nest entry hole is near the top of a 25 foot tall, white broken trunk, approximately 12 inches in diameter. 40°48.370′ N, 111°51.349′ W.

• 1 sling hanging-type, medium nest 100 feet down canyon from the milepost 2.0 sign, north-west side. 40°48.433′ N, 111°51.142′ W. Elevation 5024 Feet. Easy to see.

Totals by Type:

Grass-woven basket 10 (Probable hummingbird nests)

Circular twig 6

Platform twig 6

Basket hanging 4

Snag 6

Cliff platform 1

Subtotal 32

Bald-face wasp 6

Paper wasp 2

Subtotal 8

Total 40

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December 8, 2016

December 9th

Counting Nests

8:00 a.m. On December 8th, I completed an inventory of nests in the first two miles of the canyon done on December 1st through the 7th, and the results are not what I expected. I had thought that small birds would prefer to nest away from the road and expected to find more nests along the trails, but they predominantly nest close to the road and stream. I count thirty-nine nests in the first two miles. For insect nests, two are Paper wasp nests and six are Bald-faced Hornet nests. The remaining thirty-one are birds’ nests. Of the thirty-one bird nests: nine are delicately woven bag nests for small birds such as hummingbirds; four are hanging and finely woven grass nests suitable for small and medium sized birds; one is a cliff stick nest of the falcon pair; five are snag nests in drilled into hollow cavities of snag or dead tree trunks; and the remainder are circular or platform twig nests.

All but one falcon nest is along or adjacent to the paved road. Initially, I thought that there would be many small bird nests along the Pipeline trail in the scrub oaks, but there are none. Checking the trail a second time, I realize that the Gambel’s oaks on this west side of the canyon would be too hot in late May and early June for fledglings. Birds are nesting in the coolest part of the canyon, next to water. Mountain chickadees and Black-hooded chickadees both use snags for nesting and do not build twig nests (Hutto, p. 34-35).

There are many snags, i.e. – dead trees, in the first two miles of the canyon. In addition to the chickadees, the Hairy woodpecker (Picoides villosus) and the Northern flicker rely on snags for shelter and nesting (Hutto 34-35, Werstack, 49-50). At picnic site 7, a good example is in a 40 feet vertical snag on the other side of the creek. At its top is a tear shaped excavation that indicates there is a nest in the hollowed out tree. It is possibly the primary or secondary nest of the Northern flicker seen in this area. A second snag at the up canyon end of picnic site 9 has many smaller holes drilled in it, and these may be suitable for chickadee nesting. Birds prefer snag trunks between 10 inches to 14 inches for making a hollowed-out tree nest. In 2016, Werstack et al estimated that there are 149 million snags in Utah suitable for bird nesting, but I estimate that there are probably about 20 to 30 suitable snags in the first two miles of the canyon.

Where the Pipeline Trail skirts the based of cliffs on north side of the road near mile 1.0, a Peregrine falcon pair has a large stick nest. The nest is perched on a rock ledge about 300 feet from the trial. It cannot be accessed either from above or below by predators, and it is only faintly visible with the naked-eye. Binocular or a monocular magnification is needed to see any detail. Although the nest is currently empty, from April to June, I watched the pair and fledglings almost every day. Not in this survey, but seen last year, is a large circular stick nest in the top of an eighty foot fir tree near mile 2.4. That nest was occupied by a breeding pair of Cooper’s Hawks.

Goodfellow and Hansell describe the architectural skill that birds use to construct the many woven grass and smaller twig nests. When making hanging-basket grass or circular twig nests, some birds will use a hook technique similar to Velcro. As noted on September 5th, the design of Velcro was inspired by the burrs of the burdock plant. Birds also mimic the burdock burr. They choose twigs with small hooks near the ends or twist grasses to make hooks and as they weave a twig into the nest, they secure the twig by hooking the end around an earlier placed twig.

My instinct is that there are too few nests for the volume of birds seen during the March to May nesting season, but my bird count data suggests the number is about right. My birding log between March 2015 and May 2015 of last year (Fisher 2015) shows 166 bird sightings. Given that these involve resighting the same birds multiple times, 39 nests is reasonable. During the winter and spring, small Black-hooded chickadees, Mountain chickadees and Stellar Jays are the most prevalent bird in the canyon. Other birding logs made by Tracey Aviary professionals are stored at the Cornell University’s Ornithology Laboratory’s eBird database for the “Bonneville/City Creek” observing area (Cornell 2016). Are there and where are any missing birds’ nests?

Hornets were far more common than I had previously thought. A nest down canyon of picnic site 6 is notable. The late afternoon Sun makes it glow. It is twice the size of a basketball, and it precariously sits intertwined with the smallest upper branches at the top of a 100 foot tall Rocky Mountain cottonwood. The nest sways back and forth in the wind, but it is the most secure of the five hornet nests in the lower canyon. Although I see and photograph this nest

These hornet nests provide another link in the food chain. The hornets drink nectar and eat other smaller insects. In turn, hornets are the another food source for the many small birds seen in the spring in the first canyon mile.

In Thoreau’s “Journal” on December 9th, 1855, he visually observes his first owl in ten years, having only their heard their calls during that period.

December 6, 2016

December 6th

Filed under: Bald-Faced Hornets, Gambel's Oak, Nests, Starthistle, Weather — canopus56 @ 8:07 pm

Orange Lichens

1:30 p.m. The cold pocket of arctic air has dropped temperatures into the low twenties and with canyon winds down into the teens. The flood retention pond at Bonneville Drive has started to freeze over, and the effect on the cattail patch that grows in the pond is immediate. Previously, the dried cattails stood erect, and now they have fallen over.

As I jog up canyon, the sky is overcast with the cloud bottoms only a few hundred feet overhead, there is a wind driving light snow out of the north. By the time I reach milepost 1.0, this changes and the snow drops vertically. This kind of overcast with falling snow and cold changes perception of the canyon; it makes the canyon seem more dramatic. A buttress that sticks out on the north-west canyon wall at mile 1.1 normally looks insignificant. In the diffuse overcast light, falling snow and severe cold, it looks like a grand mountain. Four mule deer are seen on the high on the south canyon wall; three more are seen back at mile 0.2.

Between mile 1.2 and mile 1.6, lichens (Xanthomendozaon species.) growing on the Gambel’s oaks have turned from green to a dull and bright orange. With the falling snow and overcast light, this orange contrasts greatly with their host tree trunks. This color change can occur when lichens are exposed to nitrogen rich, polluted air, and such changes are used to track air pollution over time in over cities. Salt Lake City has some of the worst air quality in the nation, and the U.S. Forest Service surveys lichens at 128 plots throughout Utah, including one plot in upper City Creek Canyon. But Werstack et al (2016, pp. 43-44), researchers with the U.S. Forest Service Rocky Mountain Research Station, conclude that Utah’s lichens probably overstate air pollution. This is because orange-turning lichens are also correlated with drought tolerance (id). The lichens may be turning orange because they are in a drier climate and not because the air contains more nitrogen dioxide. The Rocky Mountain Research Station is currently conducting studies to calibrate the density of orange lichens by precipitation, thus allowing western researchers to use these epiphytes to monitor air pollution.

At mile 1.6, the snow on the north-west hillside emphasizes yellow star-thistles. Dried tall grasses and the star-thistles have the same hue, and I do not ordinarily perceive them in the meadows. But the ground snow makes for a differing background that allows one to distinguish between hills that are covered in grass and those that are covered in these invasive thistles. It was undesirable plants that the Utah Conservation Corps are trying to eradicate from the meadow one-quarter mile down canyon from here (October 16th).

I take my time jogging back down the canyon. I have been inventorying bird and insect nests in the canyon since December 2nd, and today I am marking each nest’s location using the global positioning system. Hornet’s nests are temporary constructions meant to last a single season. On December 2nd, I find and photograph the largest in the lower canyon between picnic sites 4 and 5. It is twice the size of a basketball, and it precariously sits intertwined with the smallest upper branches at the top of a 100 foot tall Rocky Mountain cottonwood. After three days of snow, rain, and freezing temperatures, I cannot find it again. Apparently, winds have blown it out of the tree or ice formed on it, and the weight of the ice pulled the nest from the heights.

December 1, 2016

December 1st

Filed under: Bald-Faced Hornets, Gambel's Oak, Insects, Nests, picnic site 4, Seasons, Weather — canopus56 @ 10:13 pm

Another Wasp Nest

1:30 p.m. It is the third day since the last major storm; temperatures have remained low; and as a result the trees are still covered with unmelted snow. Where the Sun does come out from behind scattered clouds, the melting process only just begins: it is so cold that a few isolated clumps of snow drop from tree branches. This is another marker for Fall: when it becomes so cold after a storm that snow does not melt from the trees for several days. Even though it is cold, a group of about 50 middle school children are on a field trip up the canyon.

Today, for the first mile, I travel slowly and systematically scan the leafless trees for birds nests. I find no additional nests beyond the hummingbird nest at mile 0.25 (October 27th), but I am rewarded by finding another large Bald-faced Hornet nest, about one and one-quarter the size of a basketball, across on the west canyon side from picnic site 4 at mile 0.5. Unlike the nest at picnic site 9 at mile 1.2, this nest is in an oak on the slope about forty feet above the road, and since it cannot be easily reached by people, the nest is still in excellent condition. This nest was probably the source of the carnivorous wasps seen feeding on a snake carcass near this location on August 20th.

I take the temperature of the stream in order to see what the trout must contend with. The air temperature is about 31 degrees Fahrenheit, but after immersing the inexpensive mercury thermometer into the stream, the mercury rises to 42 degrees Fahrenheit. In such water, a human would loose dexterity in less than five minutes and would become unconscious in more than thirty and less than sixty minutes.

In Thoreau’s “Journal” on December 1st, 1850, he dissects a hemisphere of moss and describes its growth layers.

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