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Fauna Series No. 1
Methods
Fauna of the National Parks
of the United States
PROBLEMS OF GEOGRAPHICAL ORIGIN
ENCROACHMENT OF EXOTIC SPECIES
UPON THE NATIVE PARK FAUNA (7)
This is a situation which is not apparent in many parks at present, but which is apt to become more and more difficult. There are three ways in which man has brought about the introduction of exotics.
(a) Many imported species of animals, notably game birds and fishes, are liberated all over the country each year in the interests of sportsmen.
(b) Exotic species are constantly being liberated by accident.
(c) Certain animals native to one part of the country actually flourish with civilization and invade new ranges in the wake of man. These are exotic in their newly occupied ranges, too.
If any animal introduced by any of the above means takes hold and spreads into a park, serious complications are bound to ensue, for such an animal would not increase if it were not able to displace another form or compete successfully in the utilization of a valuable food supply. Aside from the direct competitive effect, such introductions may have indirect influences, such as disease introduction and production of crossbreeds, but these are treated separately below.
Fortunately, most of the foreign game introductions have not been notably successful. However, captive animals which are liberated, perhaps accidentally, and do take hold are a real danger. Their vigorous adaptive qualities are a menace to native wild life. The opossum, which has recently arrived in Sequoia National Park, is an example. The same is true of the animals which thrive and spread where man goes. They are exceptionally adaptive and aggressive, or they would not have been able to go with him. Certain ground squirrels and the coyote are notable examples.
Effective ways of dealing with this type of problem remain to be discovered. The size of a park is of no avail and such species do not recognize many natural barriers. It is to be hoped that some practical means of preventing encroachments will be found before it is too late.
Coyote in Mount McKinley. – The spread of the coyote is a difficult and insidious problem. The reasons for its sudden spread over vast new territories are too controversial to be discussed here, but this outward movement is certainly associated with the changes which human populations have wrought. In Mount McKinley National Park its invasion is looked upon with great alarm.
Regarding the spread of the coyote, E. A. Goldman 14 says:
"Formerly they occupied the western plains and basal mountain slopes from western Canada and the United States south over the tableland of Mexico, and the tropical savannas along the Pacific coast as far as Costa Rica . . .
"In recent years coyotes have pushed northward, however, from British Columbia and Yukon Territory into the Yukon Valley and are reported to have reached Point Barrow, Alaska, and the mouth of the Mackenzie River in Canada . . .
"According to a resident of Telegraph Creek near the Stikine River, Canada, no coyotes were known in that section prior to 1899 . . .
"The movement into new territory evidently began in early days. Vernon Bailey states that coyotes were absent from parts of southeastern Minnesota prior to 1875 when they first appeared in Sherburne County, presumably from the great prairies west of the Mississippi River. When they became common, the red foxes, formerly numerous, practically disappeared . . .
"Coyotes entered the upper peninsula of Michigan about 1906, and have even gone into forested sections near the coast in Oregon . . .
"They are also being reported from localities east of their former habitat on the western plains. . . . Small colonies are reported in western, central and southeastern Alabama."
In his field notes, Dixon reports the skull of a coyote which was killed at Mount McKinley Park in 1926. Since that time the coyote has been gradually encroaching on the park. Similar experiences elsewhere indicate that it will tend to displace the abundant Alaska red fox, and perhaps the wolf, too, in the only national park where that animal still figures. The effect of a new and formidable enemy upon ptarmigan, curlew, mountain-sheep lambs, caribou calves, etc., can only be conjectured.
Mr. Stokley Ligon's analysis of the problem, which applies here very well, is essentially this: The coyote is beneficial in its own range and habitat; but when it gets outside of its own range, as it has done many times, it becomes a different animal and is destructive.
First of all, it is the aim of the National Park Service to maintain primitive conditions in the national parks. If this is to be accomplished, the coyote, where it is native to the park (it is clearly not native to Mount McKinley), has as much right as any other member of the park fauna. It is to be considered just as worthy and desirable as elk, moose, or deer. Indeed, when it is seen, it is a great attraction. There is sometimes a tendency in men in the field to hold any predator in the same disreputable position as any human criminal. It seems well to comment that no moral status should be attached to any animal. It is just as natural (just as much a part of nature) for coyotes to prey upon other animal life as it is for trees to grow from the soil, and nobody questions the morality of the latter. This is one angle of the situation.
The other side is that in relatively small areas, such as Mount McKinley and Yellowstone, where the wild life is of greatest importance, it is impossible to preserve that wild life and allow the encroachment of exotic predatory species or of abnormal numbers of the native ones from the outside. The antelope and mountain sheep of Yellowstone could be easily exterminated and the loss would be great, whereas the coyote is of such wide distribution that its extermination in Yellowstone is not probable. Even if it were exterminated in that particular area, it would soon reinvade. Actually it is remarkably abundant, though some control work is carried on.
The logical course of action seems to be this: If coyotes are present in a park in greater numbers than formerly but give no indications of unusual damage, they should not be molested. We do not know enough about the causes of their increase yet to justify steps against it. In Mount McKinley, where the animal life is of great importance and where the coyote does not belong, every safe step should be taken against its encroachment as an exotic and an alien. In Yellowstone, where certain species such as antelope, mountain sheep, trumpeter swan, and sandhill crane need special protection, the coyote must be controlled. Mount McKinley and Yellowstone are at present the only parks where circumstances clearly justify coyote control.
Inasmuch as there is no way of preventing the invasion of the park at the boundary line, the word control is used advisedly. It is the only way to meet the coyote problem. The solution could be a satisfactory one if there were any practical selective method which could be used. Shooting is selective, but it is costly and not sufficiently effective for the coyote. Trapping is the next best. It is effective but not selective. In Mount McKinley the prized foxes and wolves, as well as wolverines and others, would suffer, too. Poisoning, of course, could not be allowed. It would be better to have the coyote. When a satisfactory method for taking coyotes without harming anything else is discovered, one of the most puzzling of all wild-life problems will be solved.
14 The Coyote–Archpredator by Goldman, E. A., Journal of Mammalogy, Vol. XI, no. 3, August, 1930, pp. 327-329.
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Feb 1 2000 07:08:48 pm PDT
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