March 1942

Vol. XXI March, 1942 No. 3

SKIING DOWN FROM HORSE RIDGE

THE MONTHLY PUBLICATION OF THE YOSEMITE NATURALIST DEPARTMENT AND THE YOSEMITE NATURAL HISTORY ASSOCIATION

F. A. Kittredge, Superintendent C. F. Brockman, Park Naturalist M. A. Beatty, Assoc. Park Naturalist H. C. Parker, Junior Park Naturalist

VOL. XXI MARCH, 1942 NO. 3 A WINTER TRIP TO OSTRANDER LAKE

By C. Frank Brockman, Park Naturalist Although the climb along the crest that flanked Horse Ridge to the east had not been difficult, we were content to rest. The rings on our ski poles, upon which we leaned heavily, punched circular cylinders in the snow, enlivening by the contrast of their shadowed patterns the sparkling brilliance of the surface. Below, the pattern of our tracks gave evidence of the devious route from the ski hut that brought us, by a series of broad traverses, to our vantage point. Yet it was not fatigue but the commanding boldness of the far-flung winter panorama that brought a temporary halt to our ascent. Sharply etched against the morning sky was the rugged outline of the High Sierra, a tumbled mass of awe-inspiring jagged pinnacles, beetling cliffs and monumental buttes; a wilderness in white. By the nature of its rugged contours it gave visual testimony to the immensity and power of the forces which had brought this great mountain rampart into being. Mt. Hoffman, Mt. Conness, and many others loomed upon the distant horizon, while dominating the eastern skyline lay that galaxy of majestic peaks which comprise the Clark Range, their ragged crests cold and foreboding in winter's ermine and accentuated in height by the deep-set, glacial-carved amphitheaters or cirques, nestling amid the heights, and the proximity of the broad, intervening silhouette basin in the foreground. The outline of Horse Ridge itself, together with that of near-by Buena Vista Crest, implied that here too once existed a place of glacial origin. Though of minor extent in comparison with the mighty "river of ice" that played such an important part in the fashioning of Yosemite Valley, it nevertheless had sufficient power to quarry a cirque of considerable proportions. In summer this area is bare of snow and the sturdy stone ski hut stands deserted in the sparse timber on the shore of Ostrander Lake. Now the drifts which clung to the precipitous northern slopes—which is rarely affected by the rays of the winter sun—beckoned with an invitation to an exhilarating run through unbroken, powder snow.

One by one each member of the party dropped swiftly over the brink of the cirque along the slopes of the basin, descending by a series of "christies" of varied dimensions, depending upon one's prowess with the hickory blades. Ostrander Lake rapidly assumed greater proportions as we swept toward the margin of its frozen snow-covered surface, now but dimly discernible by the contrast of its level surface against the surrounding, more rugged terrain. Several minutes later and nearly one thousand feet lower, at the entrance of the ski hut, we surveyed the intricate pattern of intersecting tracks which marked the route of our swift descent. There are many such compensations awaiting those who ski "off the beaten track." Removed from packed slopes and well known runs, each stretch of terrain presents an individual problem, which adds zest to this popular out-door sport. Often outlying sections, such as the north slope of Horse Ridge offer excellent snow conditions when other more exposed areas are sometimes disappointing. The investment of time and effort, often required in reaching such vantage points, is amply repaid with interest by the exhilarating mountain panoramas which unfold with each lofty objective gained. These were our thoughts as we turned our skis homeward along the 4 1/2 mile trek to the terminus of the winter road at Bridalveil Meadow.

THE OYSTER SHELL SCALE INFESTATION OF THE QUAKING ASPEN AT SWAMP LAKE MEADOW

By Sherman Hansen and Iver Madsen, Field School, 1941 During the past four years, the Yosemite School of Field Natural History has been studying closely the infestation of the Oyster Shell Scale (Lepidosaphes ulmi) on the grove of Quaking Aspen (Populus tremuloides) at Swamp Lake Meadow. The trees were growing densely in a narrow margin around the south and east side of the swamp. It will be of interest to follow this problem in the future to keep check on the number of large trees, the extent of their infestation, and the rate at which the young trees are affected by the scale. This rapid phenomenon now in progress is extremely interesting, because the plant is in an environment which should be unfavorable to its growth, and also because the evidence seems to point to rapid extinction unless a strain is developed by natural selection which is immune to this insect. In 1938, Mr. Joseph Dixon first discovered the trees were infested. At that time only a few were losing their leaves, and the scale was not very noticeable. In 1939, the Field School class reported that a stand of at least 50 trees, averaging 25 to 40 feet in height were almost entirely wiped out. The young trees, 2 years old approximately, were infested, though they retained their leaves. In 1940, the progress of the scale around the south side of the area was reported to be very rapid. At this time 30 trees out of approximately 50, over 10 feet in height were dead. Those which were living showed life only in the uppermost branches. At the east end of the meadow, 35 trees remained alive; there being only a few dead trees in that grove. The young trees showed signs of infestation throughout the whole area. The 1941 class found the infestation had taken a heavy toll. On the south side of the area 3 trees remained alive, while in the east grove only 15 were still living. The young

aspens were heavily infested, but none of these were dead. The average age of this reproduction was 4 years, as determined by the annual growth ring count. These trees ranged in height from 3 to 9 feet, the average being 4.7 feet. On 34 young trees the percentage of mature oyster shell scale and the percentage of scale in the reproductive stage were noted. Among these trees the percentage of mature scales ranged from 0 to 20 percent with an average infestation of 4.71 percent. The scale in reproduction ranged from 0 to 70 percent with an average of 9.85 percent.

As the observer surveys the situation; many questions and problems confront him. A few of these follow:

1. The ground level of the mixed cedar and green aspen grove is about 2.5 feet higher than the surrounding area.

2. Most of the dead trees have a trunk diameter of about 5 to 10 inches, but the trees now seem to become infested when as small as one-half inch in diameter.

3. The living trees are in two groups; the mature trees, and the young trees whose trunks range from one-fourth inch to 2 inches in diameter.

4. A question of considerable interest is how long the aspens will remain in their habitat and whether or not this low altitude habitat is predisposing factor to the great susceptibility to the scale, and its consequent high fatality.

MAMMALS OF PUPPY DOME

By Ranger-Naturalist M. D. Bryant Puppy Dome is a small outcrop of Cathedral Peak granite located between Lembert Dome and the Dana Fork of the Tuolumne River in the eastern end of Tuolumne Meadows. It is a typical roche moutonnée, sloping gradually on its eastern side, and dropping abruptly at its western margin. Glacial polish and erratics are present on its sides and summit. Scattered heaps of large boulders occur about its base. This dome is of particular interest because of the variety of habitats provided on and near it, and the resultant richness of animal life concentrated in the immediate vicinity. Lodgepole Pines are numerous on the eastern slope of the dome, and occur in a loose stand about the base. Many young trees are growing in the places where the older trees have been recently killed by needleminer and bark beetles. The pines provide food and shelter for the Tahoe Chipmunk, Sierra Chickaree, and the Yellow-haired Porcupine. The first two species are abundant, particularly, on the eastern slope. Only one porcupine has been seen near the dome. This one was seen at 7 p.m., July 10, 1941

Among the boulders at the southern base of the dome, where it was feeding upon Mountain Hemp. Toothmarks on the pines and droppings among the rocks showed that the porcupine had been in this area for more than a week. When frightened it took refuge under the boulders. On August 6, 1941, two half-grown Mountain Weasels were sunning and playing about a small pile of boulders at the northeast base of the dome. Adults and young were seen in the same place early in August, 1939. It thus appears that the weasels have occupied this site for the past several years. This is understandable in view of the fact that the boulder heap provides excellent protection against the enemies of the weasel; a place to rear the young, and food that is available near-by. Belding Ground Squirrels occur in the open meadow only 60 feet away. The young begin to appear above ground during the latter part of July. These, undoubtedly, provide the greater part of the food for the weasels. A few Golden-mantled Ground Squirrels are present on the eastern slope of the dome, and seldom enter the meadows proper. Water is available on the north and south sides of the dome throughout the summer. The moist meadowland northeast of the dome with its scattered groves of Lodgepole Pine is a favorite site for Mule and Blacktail Deer. The identification of these deer is based upon the character of the tail, which varies from that of the typical Mule Deer to that of the typical Blacktail. Hybrids undoubtedly occur here. The deer spend most of the day resting in the groves of trees, and feed principally in early morning and late afternoon. A doe was seen here almost every day from July 7 to July 25, 1941. She gave birth to a fawn about July 20. Badger diggings are present in the meadow, and Pocket Gopher workings occur on the eastern slope of the dome. Droppings of the Whitefooted Mouse have been found on and under down trees at the base of the dome, and adults have been seen on several nights in the immediate vicinity. A female gathered cotton from a pillow in a cabin located 50 yards north of the dome; made a nest, and gave birth to three young during the night of August 6, 1941. A half-grown male was also present in the nest.

FIELD SCHOOL CANCELLED

By M. E. Beatty, Assoc. Park Naturalist It is with regret that we announce the cancellation of the 1942 session of the Yosemite School of Field Natural History. The decision to temporarily suspend operation of the school was made by the Director of the National Park Service in view of the need for conserving man power and funds, and the fact that the school draws students mainly from men of draft age. The Yosemite School of Field Natural History is the official training school for naturalist work in the National Park Service, and has operated each summer since 1925. Twenty students have been selected each year from applicants representing every section of the country, and given seven weeks' intensive training in interpretive work. More than a hundred graduates have been employed by the National Park Service in either permanent or temporary capacities. It is the desire of the Director that the program of the Yosemite School of Field Natural History be reinstated as soon as possible, and anyone interested in applying for the school may write in to us requesting that their names be kept on file for notification when the school is reestablished. 1941 Class - Yosemite School of Field Natural History

WOOD DUCKS—A NEW NESTING RECORD FOR YOSEMITE

By Ranger-Naturalist Enid Michael For the first time in several years the Merced River came up high enough to overflow its banks and to form ponds in the low lying sections of the Leidig Meadow. On May 2, 1941, when walking across this meadow with my friend, Mr. Fitzpatrick, the local assistant postmaster, we flushed a pair of Wood Ducks (Aix sponsa). The birds circled the meadow a couple of times and then headed away up the valley. We searched along the river as far as Mirror Lake, but failed to find the birds. In the May bird report the adventure with the Wood Ducks was reported as my first record for the female Wood Duck in Yosemite Valley. It did not occur to me that this pair of birds might be thinking about nesting in the valley. The pond, bordered by tall rushes and saw-grass, offered ideal nesting sites for certain kinds of ducks. As a matter of fact, years ago in seasons of high water, a pair of Mallards had nested and reared families on this very pond. Why then, when I saw a pair of Wood Ducks rise from this pond, did I not suspect their intentions? I don't know why I did not suspect them, but anyway as it turned out I had evidently overlooked a bet. On July 29, Mr. John Augsbury, who has spent many summers in Yosemite National Park, came to me and reported having flushed a strange duck from the pond in Leidig meadow. The bird acted as though it had young, and as it circled over the meadow it uttered a clear whistled high note. The next morning he and I went to the Leidig Meadow hoping to get a good look at the strange duck. The pond, lying in a hollow and completely surrounded with tall growing grasses, was so hidden from view that we could not see the surface of the water without approaching closely, and the bird was shy. Before we could see the surface of the water we heard soft clucking sounds like a mother hen talking to her chicks, and we felt sure that the duck was warning ducklings to hide themselves away. We moved a little closer, and a duck rose above the grasses, flew a few yards and settled down again. All I saw in the way of field marks was a fringe of white along the lower edge of the wings. John thought that there was a fringe of white at the end of the tail, but I did not get this. We followed the duck. Up it came again; this time in full flight it winged away over the meadow. It circled the meadow several times, and finally came to perch among the leafy boughs of a tall cottonwood. The duck was too far away and flying too fast for any head markings to be discernible, but we could see the white margin on the lower wing, and we also noted that it had a fan-shaped tail, or at least it fanned its tail as it banked the turns. On the wing the duck continually uttered an alarm note, a strange unduck-like note, not a quack nor a croak, but a double note in a raucous, nasal tone of voice which reminded me of the call of the young Sharp-shinned Hawks. We worked around the pool to a place where we could get a view of a narrow strip of water, and, comfortably seated in the shade of a cottonwood tree, we waited for the duck to come back. We waited twenty minutes and nothing happened. We thought that possibly the bird had sneaked back, and we began skirting along the margin of the pool through the tall sawgrass, when suddenly a half-grown duck dashed out from almost under our feet. When it struck the water it splattered rapidly away, pawing the surface with wings and feet to disappear from view at the far side of the pool. When we neared the cottonwood the parent bird began to utter her strange call-notes, and then she left her perch and flew out over the meadow. She probably had us under observation all the while we were waiting for her to return. Screened by the foliage we did not catch sight of her until she left the tree. The distinct white margin at the lower edge of the wing, the call-notes and the fact that the bird came to perch in the leafy crown of a tree, all put together, convinced me that the bird was a Wood Duck. On the morning of July 31, John and I were back again looking for the Wood Ducks. Luck was with us, and we both had a very good view of the female bird. When first seen she was on the ground; then she flew up and perched in a pine tree where she remained in plain sight for fifteen or twenty minutes. After the parent bird had flown across the meadow we went looking for the ducklings. Twice we managed to start a duckling in the tall marsh grass, but they were too fast for us, and too elusive, and we got but the mere glimpses of them. The duckling that we started several feet back from the water went through the meadow grass with the speed of a rabbit. We were mystified by the fact that the ducklings seen on this date were still in down feathers, and much smaller than the young bird we had seen the day before.

SPECIAL NUMBERS YOSEMITE NATURE NOTES

We are pleased to announce that the following special numbers have been revised and reprinted, and are now available at the Yosemite Museum through the Yosemite Natural History Association. Orders for any of these publications should include 3 cents for postage. Stamps will be accepted in payment: 1. Self-guiding Auto Tour of Yosemite Valley.—Beatty and Harwell, 16 pp., 18 illustrations, one map.—10 cents. 2. 101 Wildflowers of Yosemite.—Beatty, Harwell, and Cole. 40 pp., 101 illustrations by Mary V. Hood.—25 cents. 3. Birds of Yosemite.—Beatty and Harwell, 36 pp., 31 illustrations.—25 cents.

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