October 1933

October, 1933 Volume XII Number 10

THE PUBLICATION OF THE YOSEMITE EDUCATIONAL DEPARTMENT AND THE YOSEMITE NATURAL HISTORY ASSOCIATION

Published Monthly Volume XII October 1933 Number 10

A Night On Half Dome By C. EDWARD GRAVES (Yosemite School of Field Natural History — 1931)

A year ago last May I spent one of the most enjoyable nights of my life on the top of Moro Rock in Sequoia National Park. The pleasure of that experience inspired in me a desire to find out whether Half Dome offered similar allurement to one looking for moonlight thrills. Early in August my opportunity came. The night of the full moon (August 5) was chosen as a likely date for the experience.

In order to make the trip in easy stages, for I had a heavy load to carry, including sleeping bag, the start was made from Happy Isles after dinner the previous evening. The trip up the canyon on the bridle trail in the cool of the evening was infinitely more enjoyable than a mid-day hike. Camp was made soon after eight, not far from the top of Nevada Falls. As frequently happens, the first night's camp, which had been thought of in advance as merely a stepping-stone to the climax at Half Dome, was even more enjoyable than the second night.

EVERGREEN SILHOUETTES

My bed was laid in a sandy niche on a rocky ledge whence a fine sweep of moonlit cliffs and domes was enjoyed. The lights of Glacier Point were in full view and the upper arc of the fire-fall was seen at the usual time. The moon rose late over the steep hills behind the camp and skidded along the horizon all night long, never entirely clearing the tree-tops. A perfect semi-circle of trees, crowned with Christmas stars, framed the opposite view. In the bright moonlight they could nearly all be identified by shape and form. On the left edge a yellow pine and Jeffrey pine, verified the following morning; in the center a tall pointed incense cedar; on the right two sugar pines, one a magnificent scraggly specimen with black arms and hands reaching out into the night, and in the foreground a small black oak and young red fir. A too friendly deer visited camp several times during the night and, though responsible for some loss of sleep, she was to be thanked for additional enjoyment of the moonlight night.

The early morning brought me to the foot of Half Dome before the sun had made back-packing uncomfortable. The day was spent in the woods below the dome in such ways as are known to lovers of mountains and forests, the camera being an inseparable companion. In order not to have to carry too much food and water to the top, the start was delayed till after the evening meal was over, about 20 minutes to 5. By this time the last of the daytime climbers had descended and Half Dome and I were alone in the bright sunshine of late afternoon.

ASCENT OF DOME

A leisurely trip up the steel ladder on the nearly vertical face of the dome dulled the edge of my burden. Deliberate actions, destroying the sense of hurry, make almost any achievement possible. About 5 o'clock "we" were on top and preparations were made to enjoy the great drama soon to be unfolded. First, a round of visits must be paid to old friends of the plant family (See Yosemite Nature Notes, September, 1930). In the crevices of disintegrating granite many varieties of flowering plants and shrubs were gaily flourishing. The several varieties of eriogonum were particularly showy and the little ocean spray shrubs (Holodiscus discolor) were in their prime. While waiting for the first event of the drama, the sunset, a number of bedding places were smoothed out in niches of fine granite dust, the one finally to be selected depending on the direction of the wind at bedtime. At exactly 7 o'clock the sun dropped behind the line of western peaks, no clouds being present to catch the colors above the horizon. The level line of valley haze, seen through the eastern gateway to the valley, took to itself a cap of amethyst and plum purple and refused to doff it until after the moonrise, 35 minutes later.

MOON COMES UP

The drama of the moonrise, as seen from Half Dome, gains its uniqueness from the fact that there is no obstruction to the sight in any direction. The beholder is perched on a rocky stool, as it were, and insulated against outside distraction by thousands of feet of deep-lying space. No king ever had a more distinguished seat of honor. The approaching event was heralded by a faint light on the horizon, steadily gaining in intensity and extent. Hardly had the herald's sign appeared than his master, the moon, poked a corner of his bald head above the horizon, followed by two grinning eyes. The drama was fast assuming the aspect of a comedy. Perhaps it was a mood in me that lasted for a second only, for when the childish legend of the man in the moon was forgotten and the cold silver planet was floating clear of its earthly associations, the grandeur of the universe assumed its normal place in thought. Beauty so pure is almost cloying, as is any earthly experience when carried at the level of perfection too long. Going down to the lower side of the dome, which is approximately 13 acres in extent and consists of many miniature valleys and ridges, I spent a few minutes communing with human kind. The lights of Glacier Point were shining brightly across the gulf of space and the flickering of the embryo fire-fall suggested human company not too far away, as the crow flies though hours distant as measured by human effort at traversing the space.

At that moment, as if in response to the mood, three young boys, the oldest not over 15, emerged over the top of the ladder and announced

that they had traveled since morning without food to see the fire-fall from Half Dome. An hour of hungry waiting finally rewarded their efforts. What an answer to the skeptic who says that there is no love of beauty in the soul of boyhood!

SUNSET HOLDS VIGIL

The fading of the fire-fall was the bed-time signal. First, the camera was set up for a six-hour moonlight exposure. This meant arising at 3:30 to close the diaphragm, lest any shreds of early dawn should mingle with the moonbeams. The warmth of the night was really surprising, there being very little breeze to blow away the daytime heat rising from the valleys. The ledge behind, on which I finally lay my sleeping bag, was hardly necessary as a wind-break. Except for an occasional turning over in bed to allow the other side to mellow a bit, the night was passed in utter oblivion of the fact that a hole bored directly through my bed would, after passing through several feet of rock, open to 2000 feet of unobstructed space. Such is our confidence in nature's immobility that overhanging rocks appear as firm as any mountain mass.

It is only fair to add that sunrise the next morning was an anti-climax. No clouds, no color. Just another day of hot sunshine through which the weary hiker must make his way to camp and a shower-bath. The sum total of the experience, however, added definite riches to the collection of mountain memories and the photographic record will assist in perpetuating its uniqueness.

Oiling for Mosquitoes in Yosemite By RANGER NATURALIST ADREY E. BORELL

Visitors to Yosemite often ask about the patches of oil which they see in the meadows or the fact that many of the pools are covered with oil. One visitor asked me why there was no oil mining in Yosemite. I told him that there was no oil to mine. He replied that he had noted several places where the oil was oozing from the ground.

These patches of oil are the result of the use of oil to reduce the number of mosquitoes. The mosquitoes deposit their eggs on the surface of quiet pools. The eggs hatch into larvae which live in the pool and are known as wigglers. These larvae breathe free air and therefore must come to the surface at short intervals to get a supply of oxygen. The air is taken through a very fine breathing tube. If there is a film of oil on the surface of the water the breathing tube becomes clogged and the wiggler suffocates. This principal also applies to most of the fly sprays.

The liquid used in the spray gun consists of an oil which breaks up into fine particles. All insects breathe through fine tubes known as trachea. The particles of oil in the air clog the trachea and suffocate the insect. This spray is not injurious to humans as a little oil on the inside of our nostrils does no harm.

BIRDS, CREATURES HURT

The use of oil reduces the number of mosquitoes, but at the same time has some very undesirable effects. In the first place the oil covered spots in the meadows are unsightly, and some forms of vegetation are killed. Many birds and other animals are weakened or killed through coming into contact with the oil. Last summer I found one mountain garter snake, one yellow-legged frog and one tree frog (Hyla) which were covered with oil and were in a weak condition. One meadow mouse was also found which had a large proportion of its hair matted down with oil. However the birds seem to suffer more than any of the other vertebrates. Each summer numbers of birds with their feathers matted down by oil are seen about the valley floor or are brought to the museum for treatment. In some cases the oil involves only a few feathers on the tail or wing. In other cases most of the body is covered. Even a small amount of oil seems to cause the bird great distress. Some of the birds die, apparently, from the direct effect of the oil, some die of starvation and others being unable to fly are easy prey to their enemies. The birds which suffer the most are those which frequent the meadows, and especially those which forage on the ground. In Yosemite the Robins seem to suffer more than other species. Black-headed Grosbeaks are second on the list. Other species of Yosemite birds which we have found suffering from contact with mosquito oil are blue-fronted jay, Western tanager, red-winged blackbirds, Brewer's blackbird and spotted towhee.

AID ADMINISTERED

It is generally impossible to save birds which have very much oil on them. In some cases we have clipped the oil-covered feathers from the bird and this seems to make them feel more comfortable. We have tried washing the birds with

warm soapy water, kerosene or rubbing the feathers with cornmeal or plaster of paris. In some cases this seems to help but in most cases the birds do not recover.

The method now used is to spray the pools repeatedly with light oil rather than to apply one heavy coat of oil which would last all season. The former method is much less injurious to the meadows and to animal life than the latter.

It is unfortunate that the meadows and so many birds and other animals must suffer as a result of mosquito oiling. But undoubtedly there would be far more complaint from the park visitors if nothing were done to reduce the number of mosquitoes.

NOTELETS

By Herbert A. Anderson, Ranger Naturalist

SONG OF YOUNG BLACK-HEADED GROSBEAK

A young black-headed grosbeak was singing a very low but complete song very much like that of the spring song of the male bird from a hidden perch high in the incense cedar back of the museum on July 23. The young of both sexes are so nearly alike that it is difficult to distinguish them at sight. This young male, however, had developed his song early and of course showed a sex difference, at least in note. I studied it several minutes to be sure of the bird's identity. The song was repeated and continued for at least 15 minutes before the young bird left the tree.

HERMIT THRUSHES NEAR MIRROR LAKE

The Sierra hermit thrush, usually associated with higher timbered altitudes from 5000 feet to the upper edge of the timbered regions, seems to have come down Snow creek this year almost to the Tenaya canyon region of the russet-backed thrush, which has long been a favorite morning and evening singer in the timber of the lower Tenaya canyon near Mirror lake.

Both species were heard clearly from the Tenaya canyon trail about a quarter-mile above Mirror lake by hikers returning from Tenaya canyon on July 11, at about 5 o'clock in the evening. Again on July 20, a nature hike party on their way to Snow creek heard both species of thrushes from the trail at about the same location.

A NIGHTLY FLY-CATCHER

By Ranger Naturalist J. E. Burgess

Being a light sleeper, I was awakened by a scratching noise, which apparently originated on the roof of my tent. Thinking it was a mouse or some other rodent, I went back to sleep and forgot the incident. Next night there was a reoccurrence, and having my flashlight, I investigated, but was unable to find the cause. The third night it happened I was lying awake, studying it over, when I thought I saw something fly inside through the small opening in the flaps. Dimming my flashlight I was able to discern a bat, probably the large brown, common at this elevation, thoroughly covering the inside of the canvas, apparently catching flies.

A check on the number of flies on retiring and again in the early morning light revealed the fact that their numbers had been materially reduced, which animal on a nightly basis was performing a very valuable service as "A Nightly Fly-catcher."

White Pelican a New Bird for Yosemite By RANGER NATURALIST C. H. O'NEAL

Look! Look! All interest in the valley views from Glacier Point, June 30, were momentarily forgotten. There, 2000 feet below, were 21 great snow-white birds with black tips on their wings sailing up the canyon in perfect V-formation. Such masters of the air were they that only an occasional beat of their wings was necessary to propel them forward at great speed. Their enormous size, their tendency to sail in unison and their perfect formation gave them the appearance of a squadron of pure white airplanes as they wheeled and circled ever in perfect accord with their leader.

The wide expanse of glistening water near housekeeping headquarters tempted them lower in hopes of a delicious meal of trout, but the campers were too abundant. Soaring higher and higher they sailed for Mirror lake. Here, too, the presence of so many people frightened them upward into the Tenaya canyon. Seemingly unable to find an opening through the canyon they wheeled and came down to Indian canyon, where they were lost to view. After a few minutes a lone scout went far up Tenaya canyon and then returned. Soon appeared the entire flock and they rapidly disappeared from view, seemingly on the way to Tenaya lake.

FIRST OF RECORD

These gigantic pelicans, with a wing spread of from eight to nine feet, are common residents on large bodies of water inland from the Salton Sea to the San Joaquin and Sacramento valleys to Lassen and Modoc counties. They are seen as migrants in Central and Southern California. So far as is known this is the first record of a pelican flight over Yosemite Valley, so it adds one more species to our growing check list for Yosemite National Park. In our May issue of Yosemite Nature Notes, 183 species and sub-species of birds are recorded as having been observed in the 1179 square miles of our park to that date. This becomes the 185th species, as a Sage Thrasher was recently observed in the valley by Mr. and Mrs. Charles Michael. The Michaels also witnessed this impressive flight of pelicans from the floor of Yosemite Valley.

A NEWBORN FAWN

By Ranger Naturalist C. H. O'Neal

"Oh! We just saw the darlingest fawn."

"Where?" I asked.

"Just over there," was the answer. The animation of the young lady was so permeating that scenery was forgotten and we went to investigate.

We were led to the north slope of Glacier Point near the tree. After a search we found the doe almost completely hidden in the huckleberry oak. She had made a flat bed and in her lying down position she was able to completely screen the fawn. As I parted the branches she got up and walked a few paces away, where she seemed more concerned with eating chocolate [text unclear] than in watching her offspring.

The fawn was flat against the ground; its knees were drawn under it; its head and neck were flat. With the exception of breathing movements and an occasional

listless wink, it gave no signs of life. No notice was taken of the movement of branches so that photographs could be made.

The instinctive reliance upon the protective coloration that has served to hide its species through the ages here too made it almost invisible. The brown of its coat spotted with white made it harmonize so completely with its background that it was hardly visible to the eye and the camera recorded only the faintest outline.

The helplessness of the new-born is their strength, for Nature extends her protecting hand to the weak.

ANIMALS AT GLACIER POINT

By Ranger Naturalist R. E. Carlson

It is remarkable how tame some of our wild animals become if they are fed and given complete protection. The deer and squirrels at the Glacier Point Hotel are fine examples of this fact. Five deer have become so tame that they constantly hang around the visitors, begging for food. Some of the squirrels are so tame they will sit on one's hand while eating.

A real banquet assembly of wild life may be observed in front of the hotel at various times during the day when visitors offer salted peanuts. The writer observed four California ground squirrels, 12 golden-mantled ground squirrels, nine Tahoe chipmunks, two blue-fronted jays and one grouse feeding at the same time in front of the hotel porch. All of these animals except the jays were feeding from the hands of guests.

TUOLUMNE MEADOW NOTELETS

By Ranger-Naturalist C. W. Sharsmith

This season, in addition to the regular all-day hikes and mountain climbs, several overnight trips have been taken to Mount Lyell and the Lyell Glacier, the highest mountain and largest glacier in Yosemite National Park. These trips leave from the meadows at noon one day, arriving at the timber line base camp that evening. The entire next day is spent on the mountain and glacier. The return trip is the following morning, arriving at the meadows by noon.

Those who have participated in previous trips have declared it one of the finest trips ever taken. The time and arrangements make it possible for any one of ordinary endurance to easily make the climb and the view from the summit is magnificent. It also gives opportunity to study that fascinating borderland of plant and animal life at the timber line and to see a real active glacier. Here one can see how mountains are being made and how glaciers work in carving landscapes. One has a far more complete understanding of the origin of the Yosemite Valley after such a trip.

The parties are limited to 16, two pack mules rented from the lodge carrying all food and equipment. The entire cost for food and mules divided up among the group is surprisingly low, less than $2 per person.

The Soda Springs are quite noticeably weaker in gas content this year. This may be due to the heavy precipitation of the last two winters diluting the water.

There has been a considerable rise in the population of meadow mice; grass cuttings are everywhere far more abundant than in the past three seasons.

HERMIT THRUSH IN SONG HELEN K. SHARSMITH,

Field School 1930, Yosemite National Park

Of continued delight to the campers who come to Tuolumne Meadows early in the season is the beautiful song of the hermit thrush. The hermit thrush is our most melodious and impressive of bird songsters and it is to the great regret of bird lovers that his song season is usually so short.

Grinnell and Storer, in "Animals of the Yosemite," give the latest date a hermit thrush has been heard to sing as July 8. This was recorded at Tuolumne Meadows in 1915. Of interest, then, are the records which have been kept of the hermit thrush song the past two seasons at Tuolumne Meadows.

In the summer of 1932 the hermit thrush was heard singing many times each day, from dawn to dusk, during the first three weeks of July. They continued to sing in the meadows, though in not such abundance, up to the 27th of July. On the 30th a bird was heard near Elizabeth lake and on August 1 the last hermit thrush song was heard at Tuolumne Meadows for the season of 1932.

The hermit thrush was in full song upon our arrival at Tuolumne Meadows this season (July 9, 1933). The golden notes of these superb songsters reverberated through meadow and forest. One bird was heard often, singing with gusto from the clump of lodgepole pines but two or three feet outside the window of the ranger-naturalist's cabin. He often started before dawn in the morning and continued his songs until twilight. It was a rare privilege, indeed, to actually watch this bird at close range as he poured forth his liquid melody.

About the 18th of July our little entertainer was heard no more and fewer and fewer became the songs of the hermit thrush in Tuolumne Meadows. On July 25, at dusk, the last song of the season was heard from near Sunset Dome.

It may be that the retarded seasons of the past two years, caused by heavy winter snows and spring precipitation, give reason for the late singing of the hermit thrush, particularly in 1932. Or it may be that the season of their song is commonly longer than has been recorded. Continued observations in Tuolumne Meadows and other parts of the park will prove interesting.

Digitized by Yosemite Online Library Dan Anderson