Fauna Series No. 5

Fauna of the National Parks — No. 5 The Wolves of Mount McKinley

CHAPTER SEVEN:
RED FOX (continued)

Bear-Fox Relationships

I do not know of any significant relationship between the fox and the grizzly bear. Both feed considerably on ground squirrels and blueberries but there is enough of this food for all. On June 28, 1940, a grizzly digging out ground squirrels was closely followed by a fox. While the grizzly excavated, the fox lay on the grass nearby. Sometimes the grizzly followed the fox, which retreated slowly before it. The fox remained near the bear for the 1-1/2 hours that I watched them. Knowing that the fox had a den somewhere in the vicinity, I wondered if it were trying to lead the bear away. Shortly before I left, the fox was sitting some distance up the hill, tall and straight, watching the bear below it. Then it trotted over a knoll out of sight.

Coyote-Fox Relationships

There were so few coyotes present in the park that there was no opportunity to learn much concerning the relationships between coyotes and foxes. Former Park Ranger Lee Swisher said that there never were many coyotes in the park and that is the general consensus. In the locality where I saw a coyote three times there were several foxes. Among others was the silver fox which I saw there at intervals for more than 2 years.

On October 10, 1939, a coyote was seen on the east side of Sable Pass. As I walked up the road toward it, it circled up the opposite slope and doubled back. A half mile down the stream a silver fox stood for a time watching the coyote approach, then galloped easily to the steep slope of Cathedral Mountain and climbed to a low rocky promontory. Here he sat and watched the coyote find his trail and begin to follow it. Previously the coyote had scented or seen the fox for he trotted forward expectantly. When the coyote commenced to climb, the fox galloped rapidly upward to the next prominence where he stopped to watch it following laboriously. Farther up the slope the fox frequently stopped to bark at the coyote until it was quite near. After the animals had disappeared near the top of the mountain, the barking of the fox could still be heard. The fox escaped, for I saw him the following spring. The incident suggested that the coyote might be in the habit of chasing foxes and perhaps capturing them at times in certain types of terrain. It showed too that in the rocky slopes the fox need not be afraid of the coyote.

The food habits of foxes and coyotes are similar in many respects, so where they both inhabit an area there is a certain amount of competition. However, this competition is probably not serious. To determine the degree to which coyotes are harmful to a fox population the study would have to be made in an area where both animals were present in sufficient numbers.

Eagle-Fox Relationships

No fox remains were found in any of the 632 eagle pellets collected. There was no evidence that the eagle affects the fox population.

Foxes are so numerous and spend so much time traveling in the open, treeless areas during daylight that the eagle would have many opportunities to prey upon them if it were so inclined. The lack of any remains in the pellets indicates that foxes are rarely, if ever, eaten by the eagle. There is some possibility that young eagles sometimes attack foxes with serious intentions but they probably learn that it is a dangerous venture. Perhaps a fox is occasionally captured by an eagle but such an incident would be exceptional.

Eagles have been observed swooping at foxes just as they swoop at almost every other mammal in the park, including grizzlies. Many of these maneuvers are in sport. On May 14, 1939, an eagle was seen soaring 30 or 40 feet over a fox which stood in the open looking grim and tense, his tail straight up in the air. (Foxes often assume this pose when excited. I have seen one holding his tail in this manner after pouncing on a mouse which he still searched for, and have seen pups at a den take this stand.) When the eagle saw us it flew away, and the fox relaxed and trotted slowly over the tundra. The pose taken by the fox is apparently one of readiness toward off an attack. If the fox should run, it would give the eagle an opportunity to strike.

Dixon (1938, p. 45) describes an incident in which he saw an eagle swoop at a fox which was crouching in the open. A second fox was driven out of a culvert nearby and when it galloped away the eagle attacked it as it ran, but the fox avoided its swoop and went into a cleft in a rock. The fox possibly would have behaved differently—probably would not have run—if he were not escaping from humans as well. To avoid humans he must run; to avoid an eagle he must stand ready for attack or discreetly retire to cover. The same maneuver was not suitable for both enemies. The incident must be interpreted in the light of this knowledge. Its significance, as I see it, lies primarily in showing that the fox can avoid the stoop of an eagle.

On June 7, 1941, an eagle was seen standing beside the entrance of one of the burrows of a fox den. I am not sure just what was taking place. The eagle would reach into the entrance with its beak and then withdraw as the fox's head emerged from the hole, its jaws wide open and snapping. When the fox's head would disappear, the eagle would stoop over the hole, only to draw back quickly as the fox's open jaws appeared again. This was repeated four or five times before the eagle flew away and the fox came out to lie on the grass. Possibly the eagle had first been attracted to the den by the presence of a dead ground squirrel or some other scrap of food.

In September 1941, a combat between a fox and an eagle was reported to a ranger. Upon investigation it was found that the animal was near an eagle with a broken wing. Examination of the eagle after it was collected disclosed no evidence that the fox had injured it. (Wildlife Report, September 1941, Mount McKinley National Park.) Apparently the fox had appeared after the eagle had broken its wing and was curious or perhaps was aware that the eagle was a potential source of food.

It is of interest to compare the relationships between the golden eagle and the red fox in Mount McKinley National Park with the relationships between the bald eagle and the blue fox on the Aleutian Islands as reported by O. J. Murie (1940, p. 198—202). The food remains of 28 eagle nests were examined and the remains of only one fox pup were found at a nest. This might even have been carrion for several dead foxes were found on the beaches. I quote (p. 201) to give the general situation and conclusions: "Depredation on blue foxes has been charged to the eagle, and this was cited by many with whom we talked. Here is a problem particularly applicable to the Aleutian Islands, since most of the islands have been leased for raising foxes. The blue foxes run wild, forage for themselves, and are usually trapped at 2- or 3-year intervals. They would seem to be vulnerable to eagle attack, living as they do on the beaches of treeless islands. Also, Aleut natives told us that eagles do take young foxes. Accordingly we gave special attention to the eagle-fox relationship. Although most of the eagle nests examined were on islands occupied by foxes, we found a fox pup in only one nest, on Rat Island. . . .

"On Amchitka Island, within 200 yards of an eagles' nest containing no fox remains, a family of young foxes was living unmolested. There was another fox family at a some what greater distance in the opposite direction. Foxes were seen on the beach within easy reach of eagles on Kavalga Island. Many such instances could be cited . . .

". . . At any rate, the evidence shows that eagles are not a serious menace to the blue foxes in the Aleutian Islands. An excellent fur crop is generally harvested on islands with suitable productive beaches."

The results of the bald eagle-blue fox study in the Aleutians are similar to the results of the golden eagle-red fox study in Mount McKinley National Park. The considerable data available indicate that neither the bald eagle nor the golden eagle is a serious enemy of foxes.

Wolf-Fox Relationships

I was especially interested in the relations between wolves and foxes because the statement has frequently been made that wolves are destroyers of foxes. It soon to me became obvious that a large fox population could maintain itself in a territory inhabited by several wolves, for foxes were unusually numerous over all the north side of the park east of Wonder Lake. The area west of Wonder Lake was not investigated. In the range of the wolf family on East Fork I observed one fox den in 1939, two in 1940, and five in 1941. So far as I know none of the foxes was destroyed by wolves. Only one of the 1,174 wolf scats examined contained fox remains.

Foxes seem to have no fear of wolves. On July 23, 1940, a red fox sat watching a wolf 60 yards below it. Later the fox trotted along parallel with the wolf as the latter traveled across the slope. When the wolf descended the slope, the fox followed it a short distance down. The actions of the fox showed a confidence in its ability to evade the wolf.

On July 19, 1941, some members of a road crew saw a black wolf sniffing about the vicinity of a fox den. An adult fox followed the wolf closely and barked at it from a distance of a few feet. Once the fox ran off as though it were trying to entice the wolf away but returned when the wolf did not follow. The wolf paid no attention to the fox. It was searching for cached food items. Wolf scats at the fox den showed that the wolves had visited the den previously. Mr. Brown of the Alaska Road Commission told me about the incident, but though I hurried to the den the wolf had gone before I arrived. However, I saw the wolf about 2 miles beyond the den and later saw it catch a calf caribou and photographed it as it fed and then cached the remains. The incident again illustrated that foxes have full confidence in their ability to run away from or avoid a wolf. I have observed magpies and short-billed gulls (Larus canus brachyrhynchos) searching for morsels at a fox den. The den is a source of food which many animals know about.

At Teklanika Forks in 1939 a gray wolf was observed sniffing about a fox den, perhaps looking for food. Wolves probably visit many fox dens in search of scraps, especially if their food supply is a little scant.

The relationship between the wolf and the fox seems to be one of mutual gain. The wolves benefit by having available a large number of old fox dens which they can enlarge for their own use. It is a simple matter for the wolf to enlarge a burrow and much easier than digging a new one. Although the fox burrows are too small for the adult wolves, the pups can use the entire system of burrows. So far as I know, all the wolf dens found in Mount McKinley National Park were renovated fax dens.

Although the fox loses a few food items when a wolf ransacks its den site, the loss is insignificant. If there is food present it is a surplus which can be spared, whereas if food is scarce there will be none lying around.

Generally when a wolf makes a kill of a large animal it is shared by the fox, for after the wolves have eaten there is usually some of the carcass remaining. Signs at a great many of the carcasses examined in the field showed that foxes had shared in the spoils. Much of the food supply is made available to the foxes in winter when their food is scarcest. Here the fox's large gain is the wolf's small loss. Since the fox eats much less than the wolf, the loss is usually not serious and to a degree represents a surplus, although at times of course this surplus may be later needed by the wolf.

Wolves often cache the remains of a carcass after eating their fill, and the foxes commonly track down the wolves and rob the stores. Such an incident took place on October 4, 1939. A wolf had killed a lamb on Igloo Creek in the morning and, after feeding, had removed a part of the carcass and carried it away with him. The ground was covered with 2 or 3 inches of snow, sufficient for good tracking. The first indication I had that the wolf was carrying a load was the blood and hair on the snow where he had placed it on a knoll when he had stopped to look around. At two other little prominences he had laid the meat on the snow. Although the wolf track was only a few hours old a fox was ahead of me on the trail. He probably had gotten the scent of the sheep meat from the vegetation along the way. In one place the wolf had back-tracked for 15 yards, had jumped off the trail 8 feet to one side, and then had wandered about in several loops. At this point the fox tracks circled about as though the fox had been having some difficulty in unraveling the trail. The wolf resumed his direction northward through some wet tundra, walking in shallow puddles of water apparently by choice to destroy his scent. After passing through some woods he came to Igloo Creek and there his trail disappeared. The fox had come to the stream and had stood with front feet on a snow-covered rock in the shallow water beside the shore, apparently sniffing for the scent. In two other places, tracks of the forefeet on a rock showed that the fox had stood facing the stream looking for the lost trail. The wolf had walked in the water for 15 yards and had come out on the same side of the stream again. The fox and I both followed down the stream until we came to his tracks. Down the bar 300 yards the tracks led directly across the shallow stream. Here the fox, without hesitating, had also crossed the stream. After following the bar a little farther the wolf went into the woods where his trail made an S. And there beside a tree was the cache, already raided. Here I caught a glimpse of a cross fox carrying something, probably sheep meat. All that was left at the cache was much loose sheep hair. The cache had been covered with lichens and snow. Beyond this point the wolf and fox tracks continued for 150 yards to a second cache beside a hummock. The wolf apparently did not believe in having all his eggs in one basket.

But both baskets had been robbed for the second cache was also raided. The wolf tracks continued through the woods and led up a long mountain slope. Blueberries on the ground, which he squashed as he walked, colored many of his footprints purple. The fox tracks stopped at the second cache. The fox probably knew that the wolf had cached all his load. The behavior of the wolf seemed to show that he was aware that he would be followed by foxes for it seemed he made deliberate attempts to throw them off his trail.

All the data gathered on the wolf-fox relationships strongly support the conclusion that the fox population has not been harmed by the presence of the wolves in Mount McKinley National Park and the adjacent region north of the park, and that both species can subsist in the same region in good numbers.

Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT
http://www.nps.gov/history/history/online_books/fauna5/fauna7b.htm