History of the Sheep in Mount McKinley National Park
The history of the Dall sheep in Mount McKinley National Park, so far as we know, goes back over a stretch of many thousand years. It would be intensely interesting to know the detailed history of the sheepthe many vicissitudes during this long period. But through it all the sheep have survived. There probably have been many periods of sheep abundance, and many periods of sheep scarcity. During a series of easy winters, the population probably built up and overflowed the rough country into the lower gentle hills. Wolf populations may have had their own periods of scarcity and abundance, and, depending somewhat on the status of the caribou, preyed extensively upon sheep at times, or affected them little. When hares disappeared, leaving the lynx population stranded, no doubt the lynx in desperation hunted sheep. The history is an ever changing mosaic. It is to make possible the continuation of this natural course of events that Mount McKinley National Park has been established.
From 1906 to 1923, when I first visited Mount McKinley National Park, the sheep population was consistently high although there was considerable sheep hunting in the area up to 1920. Charles Sheldon (1930) found sheep abundant during his days there from 1906 to 1908. An "old-timer" told me that in 1915 and 1916, when he had hunted sheep in the area, they were very abundant, and that one winter he had sold 42 sheep carcasses. At this time several other market hunters operated in the region. Many sheep were apparently killed for the market and many were fed to the sled dogs used in hauling the meat. At an old crumbling cabin on East Fork River I found many old ram skulls, most of which were heaped in a pile. There were 142 horns, so at least 71 rams had been brought to this camp. The skulls had been split open, probably to make the brains readily available to the dogs.
O. J. Murie in 1920 observed a market hunter operating at Savage River. The hunter had shot a number of sheep on these slopes. At that time many sheep were wintering on the ridges south of Savage Camp.
In 1922 and 1923 I observed sheep summering in considerable numbers at the head of Savage River where now scarcely any are to be found. In 1923 they were plentiful but probably not as plentiful as during the next few years because extensive market hunting had stopped only 2 or 3 years before.
From 1923 to 1928 there was a steady increase in the population. Some think the peak was reached in 1928. The numbers were estimated at 10,000 and upward. Two rangers estimated the population as 10,000 and another member of the park force estimated it as 25,000. No organized counts were made so far as I know, so it is hard to evaluate the estimates. Nevertheless the population in 1928 was no doubt large. With so many sheep occupying the ranges there was not sufficient food for all among the cliffs so that many wintered on gentle slopes and down along the river banks 4 or 5 miles from the mountains. The animals were forced into the lower hills and valleys to feed. On some ridges there were patches of dead willow which I presumed had been killed during the high density of the population. I feel confident, from all the information I have been able to gather, that there were at least 5,000 sheep in the park during the peak. How much larger the figure was it is difficult to say, but it is possible that there were as many as 10,000, as some have estimated.
During this period the history of the wolves is briefly as follows: In 19068 Sheldon (1930) found wolves among the caribou herds but few among the sheep. He observed two different wolves hunting sheep in the Toklat River region. Possibly they hunted more to the east of Toklat River, but apparently there were only a few wolves among the sheep. John Romanoff, who hunted sheep in the park in 1915 and 1916, said he did not see a wolf track in the area at that time. In 1922 and 1923 my brother and I saw no wolf signs at Savage River, nor had my brother seen any wolf tracks on a trip up Toklat River in December 1920.
Former Superintendent Karstens in his monthly report for December 1925, mentions the presence of wolves in the park and that they seemed to be on the increase. The wolves were not considered abundant in 1926 and 1927, but in 1928 it was felt that there had been a decided increase. From 1928 to the present time wolves have persisted in the sheep hills, apparently in fair numbers. No one knows what variation has taken place in the wolf population during this period. One ranger estimated 50 wolves in 192930 when he felt wolves were at their peak. I estimate the 1941 population at between 40 and 60 wolves in the sheep hills. The population may not have varied greatly from that figure during the last 10 or 12 years.
There apparently had been no severe winter during the time the sheep herd built up, although some sheep apparently were adversely affected by winter conditions at times. One of the rangers captured a ewe in the deep snows of Sable Pass in 1927 and the animal died a few days later. A weak ram found at the same time but not brought in was dead when seen again.
The snow conditions in the winter of 192829, according to reports, caused quite a large loss among the sheep. The Park Superintendent's report for March 1929, describes conditions as follows: "The winter has been a hard one on sheep with the deep snow and storms. They have been driven down from the ridges and into the deep snow of the flats in their effort to get feed. They were even noticed out on the flats near the north boundary 4 miles from the range."
In the April report the following statement is found: "The month of April proved to be the hardest one of the year for sheep. Very few places were kept blown bare by the wind. What few bare spots there were, were soon grazed off and the sheep ranged into the flats in search of feed. It is believed that many sheep starved to death. In the vicinity of Igloo the rangers picked up three rams and three ewes with lamb, though one of the ewes was too far gone to recover and died after a few days."
The account is continued in the July report for 1929: "Nyberg and Myers returned from a trip into the mountain [McKinley] on the 27th and reported that the wild sheep in the park look to be about as numerous as ever notwithstanding the hard winter and heavy snows, and report that most of the losses occurred in deep passes where they were marooned in the heavy snow and blizzards of March and April."
One ranger wrote me that the wolves had killed many sheep that winter, but that "the big jolt" had come in April, when heavy snows covered the food. For the part of the range he had investigated near Headquarters he estimated that a third of the sheep population had died. He said that those sheep that perished were mostly the old and the yearlings.
In the spring of 1929 there apparently was a fairly good lamb crop. The following two winters were not severe, but heavy wolf predation on the large sheep population was reported.
The most serious reduction among the sheep apparently took place in the winter of 193132, which was much more severe for the sheep than that of 192829. The Park Superintendent's report for December 1931 states that the rangers were experiencing difficulty in making patrols because of the heavy snows and that "from all indications the sheep are going to have a hard time finding forage this winter." The January 1932 report states that the month was very cold, that the sheep were all in good condition, but that the late snows had driven them well up toward the summits of the mountains. In February 1932 it was reported that all records for snowfall had been broken, that 72 inches had fallen in 6 days, and that the winter of 193132 would be remembered as the "year of the big snow." The Superintendent reported: "During the heavy snowfall which came on the 3d of the month, I was alone at headquarters and taxed to the utmost in shoveling snow from the roofs of the buildings. It was thought for a while that several would go down, as the snow was 4 feet deep in places. I called up on the phone to get a man from the station to come up and help me out. He left there at 8 a. m. and arrived here at 3:10 p. m. It took him just 7 hours to go the 2 miles notwithstanding the fact that he had on a good pair of snowshoes. The heavy snows that came during the fore part of the month were followed by 2 days of rain, then below-zero weather, and a heavy crust was formed which has caused untold suffering amongst the wild animals of the interior of the park. This is especially true concerning the moose. Their legs from the knee down are worn to the bone, and each moose trail is covered with blood. It is possible to walk right up on a moose as they have not the courage or strength to run away."
In the April 1932 report, after some investigation of conditions among the sheep had been made, the following statements are found: "We have suffered a severe loss of mountain sheep during the winter as a result of the heavy snows; also the predatory animals have taken their toll. Ranger Rumohr counted 15 dead sheep while on his way in from Toklat. He examined many of the carcasses for evidence of wolf kills, but in most cases it appeared that the deaths were the result of starvation."
Former Ranger Lee Swisher wrote me that he found a great many dead sheep that spring which were not wolf kills. Dixon (1938, p. 231) reports that Ranger Swisher had told him in August 1932 that he did not believe there were more than 1,500 sheep in the park at that time as contrasted with an estimate of 10,000 to 15,000 he had made in 1929. In view of the deep snow and the severe crust, and the huge sheep population, which quickly consumed the food available on the more favorable ridges, it is not surprising that such a catastrophe occurred.
The lamb crop in 1932, probably because of the hard winter, was very poor, so that deducting normal winter losses, the numbers must have been smaller in 1933. Ivar Skarland, anthropologist of the University of Alaska, told me that in a trip into the park in April 1931 he had counted 830 sheep. In 1934 he made the same trip in April and saw scarcely any sheep, which agrees with the other reports on the reduction of the population.
For the period from 1933 to 1939 variations in sheep populations are not well known. One ranger thought the ebb was reached about 1935 or 1936. In 1939 there was an excellent lamb crop and a good survival of the yearlings of the previous year. Another ranger said he thought there were more sheep in 1939 than there had been for 4 or 5 years.
The yearling losses were heavier in the winter of 193940, and in the spring of 1940 the lamb crop was far below par. These losses and the small lamb crop were a definite set-back to the population. The lamb crop in 1941 was excellent, but there were very few yearlings because of the few lambs the year before. The present population is estimated to be between 1,000 and 1,500 sheep, perhaps not far different from the population in the spring of 1932, when Lee Swisher estimated the number at not more than 1,500. It appears to me that since 1932 the sheep population has not varied greatly.
That, in brief, is the recent history of the sheep in Mount McKinley National Park, so far as I have been able to outline it from available records.