England | Ecology

 A year or more may elapse before it is finally settled, but there is little doubt that a great astronomical observatory will shortly grace Mt. Wilson and make Pasadena a central point of interest to the scientific world! – Pasadena Star, April 8, 1892

Today, I ran the Mt. Wilson Toll Road. In fact, I run that “road” often, and very well may run it again each of the next two days. It’s a fairly quick and somewhat easy way to get in 20 miles of trail running, and is an excellent choice for me when I have other things to do with my time that day. It occurred to me as I was out there that it also would make a good opening for a series of write-ups I want to do on the basic ecology observed along popular trails. The list of bird species observed today tallies to 48. All photos and observations included herein were taken by me, today, during the run. Photos were taken with a Samsung S5 Active phone (as carrying a real camera isn’t easy or desirable on most runs), and the Birdlog app on the phone is where species are recorded. All bird observations, while running, are without binoculars and are based on either close visual observation or identification of songs and calls.

The Mt. Wilson Toll Road, for all practical purposes, is just a wide trail, with a large variety of habitats that change with elevation, slope, and aspect. Under the direction of the Mt. Wilson Toll Road Company, construction of the road commenced at Eaton Canyon in February 1891.  By July of that year, the 10 mile-long road was opened to the public (despite problems with a grizzly bear and its cub at Henninger Flats) with a fee of 25 cents for hikers and 50 cents for horseback riders (Robinson 1991). Today, there is no toll charged for use of the road. In fact, the entrances are gated and nobody can enter with a vehicle without authorization and access to a gate key. Even then, the road is usually not passable in its entirety to motor vehicles because of large boulders and rock slides, which are almost always covering some portion of the road. The record storms of the winter of 2005 collapsed the road in its entirety at Eaton Canyon, and it wasn’t rebuilt for several years.

Eaton Canyon Park

I begin my run at the main entrance of Eaton Canyon Park. I will often park on the street outside of the park, but today I parked in the overflow lot at the extreme southern end. Eaton Canyon is a park operated by the County of Los Angeles. The park has excellent facilities, including a nature center, but is very popular and often packed with people who seem to care little about leave no trace ethics, being extremely noisy (often blasting loud music) and throwing their trash on the ground. To avoid some of the crowd, I stay left and take the back trails through the oak woodland and chaparral gardens. I have commonly seen Bobcats (Lynx rufus) here, but not today. Today, I observe many of the bird species typically found here, including California Quail (Callipepla californica) and Acorn Woodpecker (Melanerpes formicivorus), among others. You are eventually forced to join the throngs on the main trail where you cross Eaton Wash, and head northwest. Approximately 1.5 miles in, if you survived the hordes of people, you will join the Toll Road.

Toll Road Start to Henninger Flats

The Toll Road doesn’t mess around: it immediately begins to ascend steeply, averaging approximately 500 feet of gain per mile along its length. The climb to Henninger Flats is approximately 2.5 miles. For the naturalist, there is little here to get excited about. Vegetation here is typified by moderately to heavily disturbed Coastal Sage Scrub, Coastal Sage-Chapparal Scrub, and some Chamise Chaparral (all community types follow Holland 1986). I saw few birds here, as is often the case on this route. There are few blooming flowers, except for the pink masses of California Buckwheat (Eriogonum fasciculatum). Invasive plants are everywhere: the first canyon you encounter on the climb is almost entirely vegetated by a non-native fountain grass. Other non-native grasses are also prevalent, as are Tree Tobacco (Nicotiana glauca), Spanish Broom (Spartium junceum), and Castor Bean (Ricinus communis). That said, Rufous-crowned Sparrows (Aimophila ruficeps) are readily found here (including one singing by me today), and this species is considered a Species of Special Concern by the State of California.

Everything changes upon arrival at Henninger Flats (2,600 feet above sea level). Today the home of the Los Angeles County Fire Department forest nursery and conservation center, the area was originally settled by “Captain” William K. Henninger in 1880 or 1881. The government took over the land and turned it into a tree nursery in 1903, planting the area in Ponderosa, Coulter, and Knobcone pines (Robinson 1991). Many of those trees are still present and providing shade to campers and weary hikers (and runners) today.

Those trees, while not native to that location, do harbor a considerable number of birds. Present today, among other things, were quite a few Western Bluebirds (Sialia mexicana), and several Violet-green Swallows (Tachycineta thalassina) with a single White-throated Swift (Aeronautes saxatalis). Among the Lesser Goldfinches (Spinus psaltria) was a pair of Lawrence’s Goldfinches (Spinus lawrencei), as well as a singing Purple Finch (Haemorhous purpureus). They were not detected today, but this has been an excellent spot to get Pine Siskin (Spinus pinus), which is a species not always easily found in the San Gabriels away from the high country.

As you pass out of the Henninger Flats campground area, you go through a series of buildings, orchards, gardens, and some immediately surrounding hillsides cloaked in some taller and healthier-looking mixed chaparral. Shortly thereafter, you pass to the “back” side of mountains, the vegetation changes, and things get more interesting.

Henninger Flats to Mt. Wilson Summit

Upon crossing to the north-facing slope, the soils retain more moisture and vegetation can grow more lushly. The dominant plant community quickly changes from chaparral to forest. At this elevation (approximately 3,000 feet) until you near the summit of Mt. Wilson, the whole area is putting on a wildflower show. A sampling of this can be seen in this composite image below, all of which were taken today:

Initially, the forest is dominated by live oak, with a variable but overall small percentage of Bigcone Douglas-Fir. Because the area stays cool, even on warm and sunny days unlike this one, birds will often remain active throughout the day. On this day, at the junction with Idlehour Trail (miles 5 and 15), I stopped for a few minutes and looked down into the adjacent canyon. An Anna’s Hummingbird (Calypte anna) forages on nectar from Bush Monkeyflower (Mimulus aurantiacus) immediately below. A male Purple Finch, which had been singing to my left, flies across and within ten feet of me, a blaze of puplish-pink as it passes, and perches in a tree to my right and begins singing again. Near the finch is a vocal Ash-throated Flycatcher (Myiarchus cinerascens). Behind me, in a tall Douglas-fir, are a singing Cassin’s Vireo (Vireo cassinii) and Black-throated Gray Warbler (Setophaga nigrescens), amidst a couple of Mountain Chickadees (Poecile gambeli). A loud “quock!” echos from further down the canyon, signaling the presence of Mountain Quail (Oreortyx pictus), which generally replaces the California Quail in this environment. While I’m enjoying the moment, I am on a run and have some ground to cover, so I continue on.

A mile or so further up, you progress across an open saddle and onto the flanks of a different prominence. Beginning here, there is less soil present along the road and the shrubs and trees seem to arise almost magically from white granite:

This area is not the place to be during a significant rain event. The boulders in the photo above came down during a rain event this winter, as did many others in the miles I’m about to cover.

With the increasing elevation, as well as the change in soils, the vegetation changes subtly. While it is still dominated by live oak and Douglas-fir, the astute observer will note that Douglas-fir becomes dominant, evermore so the higher you go. Also making an appearance in this area is California Bay Laurel (Umbellularia californica), known as Oregon Myrtle by folks in that state who wish to call it their own. While the birdlife doesn’t change significantly, there are some species that are more likely to be found here than further down the road, including Steller’s Jay (Cyanocitta stelleri) and Olive-sided Flycatcher (Contopus cooperi), both of which are present on this outing. Today, however, this is also where the fog (or clouds to those down below) becomes extremely dense and water is dripping from the leaves of the trees. The Toll Road becomes wet. Visibility shrinks to no more than 20 or 30 feet. The birds are quiet. As a lone runner, noises in the brush off to the side take on greater significance: What are almost certainly squirrels become almost certainly bears. The little bursts of adrenaline help to propel me along on my trek.

While the visibility on this day is minimal, you can still see the signs of the unprecedented drought, which is now in its third year. A recent paper by Griffin and Anchukaitis (2014) suggest this is the worst drought in 1,200 years based on tree ring data. A significant number of the oaks are dead or dying, including the majority of trees along the road in some stretches. Also dying are Douglas-fir and Incense Cedar (Calocedrus decurrens). As noted by the authors in the aforementioned paper, California has an extensive history of three-year droughts ended by dramatic rain years. Also, with less frequency, are much more sustained droughts. We can only hope the former occurs. Some photos of the dead and dying trees from this day are below:

At mile 7 or so, you change sides on the mountain again as you approach Mt. Harvard. Now facing the city and open to the sun (on sunny days, unlike this one), this section can feel extremely hot on warm weather days. The vegetation here returns to chaparral, but the character of the chaparral is different because of the elevation. Here, it is dominated by one or more species of scrub oak, manzanita, ceanothus, and mountain-mahogany. Dips in the terrain in some areas increase shade and moisture, bringing back live oak and Douglas-fir, but these respites don’t last for long. While it continues to be quiet on this day from a birding perspective, I do hear the song of the Canyon Wren (Catherpes mexicanus) echo up the mountainside from a canyon below. On prior runs here, I have had close encounters with both Bobcats and Gray Fox (Urocyon cinereoargenteus).

Shortly, you reach a trail junction where you can head down to Chantry Flats or elsewhere in Santa Anita Canyon, or continue on the Toll Road toward Mt. Wilson. The forest returns here. The left side, as you continue up, is a steep granite wall that is prone to crumbling in major storms, and the rock slides are evident here during this trip. To the right, on clear days, you can see the taller peaks of San Antonio and Baden-Powell. Further up the road, you can take a single track trail to the right to arrive at the summit, or continue up the road to the same destination. On this day, as I often do, I take the single track up and the road back down. Along the way, at the time of this writing, extensive brush clearance work is apparent. I am guessing this was done for fuel modification purposes, as the remaining tall shrubs were “lollipopped”, however, they left the cuttings in place, thus covering the whole mountainside in two to three feet of dry fuel. One side effect of this is severe damage to the habitat that was there, and what used to be an excellent spot to observe birds is no more.

At mile ten or so, you reach the summit, which harbors the Cosmic Cafe, the Mt. Wilson observatory, and numerous other trails to continue exploring. On this day, however, I’ll take in the view, refill on water, and return to Eaton Canyon.

The Bird List

5	Mountain Quail Oreortyx pictus
2	California Quail Callipepla californica
1	Turkey Vulture Cathartes aura
1	Cooper’s Hawk Accipiter cooperii
1	Red-shouldered Hawk Buteo lineatus
2	Red-tailed Hawk Buteo jamaicensis
15	Band-tailed Pigeon Patagioenas fasciata
5	Mourning Dove Zenaida macroura
1	White-throated Swift Aeronautes saxatalis
3	Anna’s Hummingbird Calypte anna
10	Acorn Woodpecker Melanerpes formicivorus
4	Nuttall’s Woodpecker Picoides nuttallii
2	Northern Flicker Colaptes auratus
1	Olive-sided Flycatcher Contopus cooperi
4	Western Wood-Pewee Contopus sordidulus
4	Pacific-slope Flycatcher Empidonax difficilis
2	Black Phoebe Sayornis nigricans
3	Ash-throated Flycatcher Myiarchus cinerascens
1	Cassin’s Vireo Vireo cassinii
10	Steller’s Jay Cyanocitta stelleri
10	Western Scrub-Jay Aphelocoma californica
2	Common Raven Corvus corax
3	Violet-green Swallow Tachycineta thalassina
20	Mountain Chickadee Poecile gambeli
6	Oak Titmouse Baeolophus inornatus
10	Bushtit Psaltriparus minimus
1	White-breasted Nuthatch Sitta carolinensis
1	Canyon Wren Catherpes mexicanus
25	House Wren Troglodytes aedon
35	Bewick’s Wren Thryomanes bewickii
10	Blue-gray Gnatcatcher Polioptila caerulea
20	Wrentit Chamaea fasciata
10	Western Bluebird Sialia mexicana
6	California Thrasher Toxostoma redivivum
1	Northern Mockingbird Mimus polyglottos
1	Phainopepla Phainopepla nitens
4	Black-throated Gray Warbler Setophaga nigrescens
20	Spotted Towhee Pipilo maculatus
1	Rufous-crowned Sparrow Aimophila ruficeps
10	California Towhee Melozone crissalis
20	Dark-eyed Junco Junco hyemalis
1	Western Tanager Piranga ludoviciana
2	Black-headed Grosbeak Pheucticus melanocephalus
1	Hooded Oriole Icterus cucullatus
50	House Finch Haemorhous mexicanus
10	Purple Finch Haemorhous purpureus
30	Lesser Goldfinch Spinus psaltria
2	Lawrence’s Goldfinch Spinus lawrencei

Literature Cited

Griffin, D., and K. J. Anchukaitis. 2014. How unusual is the 2012–2014 California drought?, Geophys. Res. Lett., 41, 9017–9023, doi:10.1002/2014GL062433.

Holland R.F. 1986. Preliminary descriptions of the terrestrial natural communities of California. California Department of Fish and Game unpublished report.

Robinson, J. 1991. The San Gabriels. Big Santa Anita Historical Society. Arcadia, California. 312 pages.