Part 12

These relations are not so much of the living Caribou as of their bodies after death. The principal avian scavengers in the Windy River area seem to be the Rough-legged Hawk (Buteo lagopus sancti-johannis), the Herring Gull (Larus argentatus smithsonianus), the Canada Jay (Perisoreus canadensis canadensis), and the Raven (Corvus corax principalis). These birds are evidently attracted to the vicinity of camps and trap-lines by reason of the numbers of caribou bodies lying about. On their first arrival in late May or early June, before the lakes have opened up and while food in general is scarce, Herring Gulls seem particularly prone to assemble where Caribou have been recently killed. For example, up to June 3 only a handful of these birds had been seen about Windy River. On that day several Caribou were killed, and on June 4 about 100 Herring Gulls had gathered at the scene. Their scavenger activities make it especially necessary to protect the caribou bodies in the way described in the section on Relations to man. In a few days one of the bodies (apparently not so protected) had been almost entirely consumed. The Herring Gulls operate locally only from May to September, being absent during the rest of the year. A few Ring-billed Gulls (Larus delawarensis) appeared meanwhile and attacked a caribou carcass.

The Rough-legged Hawk is far less numerous than the Herring Gull and so is a much less serious scavenger. Now and then, however, it may be noted feeding on a caribou carcass. Even the Long-tailed Jaeger (Stercorarius longicaudus) is reported in such a role. The Canada Jay and the Raven are permanent residents and are undoubtedly helped through the inhospitable winter by man-killed Caribou. On the other hand, a good many Ravens fall victims to the fox traps placed about the bodies. Charles Schweder has frequently seen Ravens following Wolves, as if in expectation of a kill. Buchanan remarks (1920: 248) concerning the Reindeer Lake region, that the Ravens "appear to remain in the vicinity of the Caribou herds all though winter." In the Windy River area the Canada Jay became noticeably more numerous in August, after the Caribou had returned from the north. The Ravens and the Rough-legs exhibited a similar increase in September and October.

The depredations of these carnivorous birds result to the detriment of the living Caribou in that they virtually force the hunters and trappers to kill a larger number of the animals than would otherwise be necessary.

References.--Hanbury, 1904: 135; Stefánsson, 1913a: 93; Seton, 1929, +3+: 108; Ingstad, 1933: 157-159; Downes, 1943: 228; Banfield, 1951a: 36, 42; Harper, 1953: 28, 60, 62-64, 72, 74, 76.

Relations to miscellaneous animals

The Schweder boys spoke of Arctic Hares (Lepus arcticus andersoni) being in the habit of eating the stomach contents of Caribou after the animals have been dressed in the field. This represents merely harmless utilization of a normally waste product, although it serves some of the natives as nerrooks or "Eskimo salad" (cf. Richardson, 1829: 245). Wolverines, Mink, Weasels, and Lemmings help to consume unprotected caribou bodies. (In the Old World the Wolverine is regarded as a serious enemy of live Reindeer [Jacobi, 1931: 243; Harper, 1945: 473].)

References.--Pike, 1917 (1892): 56-58; Seton, 1911: 252, 1929, +2+: 413, 424, 443, and 1929, +3+: 108; Harper, 1932: 23; Ingstad, 1933: 157-159; Freuchen, 1935: 93, 99; Hoffman, 1949: 12; Banfield, 1951a: 36, 41; Harper, 1953: 40, 41.

Relations to flies

Flies of various kinds perhaps cause more wide-spread, year-round misery to the Caribou than all other pests and enemies combined. It is safe to say that not a single individual in the whole population escapes their attacks, and some even succumb to mosquitoes (Gavin, 1945: 228). The various biting and parasitic flies have already been discussed to some extent in the section on Influence of insects on distribution. Harassment by these pests is believed to be the leading cause of the haste with which the Caribou are frequently seen passing over the Barrens in summer. Downes (1943: 204) has commented on the habit of Chipewyan hunters in the Nueltin Lake region of examining the legs of Caribou for swellings caused by mosquito bites. In a buck secured on August 17 the legs exhibited numerous little bumps of this sort; furthermore, black flies covered the buck's body, while scarcely troubling those of us who were preparing the specimen. Fortunately the suffering from mosquitoes and black flies on the Barrens is largely limited to the months of July and August.

Even at this season the Caribou are granted occasional relief from the blood-sucking flies. The characteristic strong winds of that region help greatly in keeping the insects in abeyance. Furthermore, both mosquitoes and black flies become more or less inactive whenever the temperature drops to the neighborhood of 45° (cf. Weber, 1950: 196), and this happens fairly frequently even in mid-summer. Finally, the black flies retire during the hours of darkness; and short as these hours are, the relief they bring is very noteworthy. These conditions offer something of a contrast to those surrounding the Woodland Caribou. It is difficult to see how that animal can secure a moment's respite from mosquito attacks, by day or night, through most of the summer. In its forested habitat there is not sufficient lowering of the temperature nor sufficient penetration of strong winds. Hard as the life of the Barren Ground Caribou may be, it seems to have a few advantages not available to the Woodland Caribou; and possibly it is these that have enabled it to attain a vastly greater population than the other species.

Of 52 mosquito specimens brought back from the Windy River area, 39 were Aedes nearcticus Dyar, 2 were probably Aedes fitchii (F. and Y.), and the remaining 11 were of the same genus but not in condition for specific determination (cf. Dyar, 1919; Weber, 1950: 196). Ae. nearcticus is holarctic in distribution; in North America it occurs chiefly on the Barren Grounds, but is known from as far south as Montana. Ae. fitchii ranges through the northern United States and Canada, north to the limit of trees. Of 26 black flies, all were Simulium venustum Say, which occurs in northern Europe, Alaska, and Labrador, south to the Adirondacks, Illinois, Iowa, Georgia, and Alabama. (Names and ranges supplied by Dr. Alan Stone, of the United States Bureau of Entomology and Plant Quarantine.) These mosquitoes and black flies were presumably the species attacking the Caribou in the Nueltin Lake region.

The effects of the two parasitic flies are felt nearly throughout the year. The adult warble fly (Oedemagena tarandi) is seen in the Windy River area in August, when the Caribou are on their southward march. On August 22 Fred Schweder, Jr., secured three of them on freshly killed Caribou and another that alighted on himself--all on an island in Windy Bay. His name for them is "deer fly." He reported seeing about 50 of them on this day (more than ever before), although he sighted only 10 Caribou. As he remarked, these fuzzy flies look much like bumblebees. Three days later, along Little River, something buzzed past me while a band of Caribou were near. It was probably this species, although it suggested a hummingbird almost as much as a bumblebee. On several subsequent August days, while numbers of Caribou were passing very close to me, I detected no more of the warble flies. In general, they might well have escaped my notice owing to my preoccupation with photography; but on August 30, when I looked for them on one of the nearest animals, I saw none. Evidently they are not sufficiently numerous (like horse-flies on cattle) to be constantly in attendance on each Caribou. In fact, a comparative scarcity (or at least difficulty of capture) may be surmised from the fact that the Canadian Arctic Expedition 1913-18 brought back only three adult females--one from Teller, Alaska, and two from Bernard Harbour, Dolphin and Union Strait (Malloch, 1919: 55). Weber (1950) collected no Oestridae in Arctic Alaska.

Apparently there has been scarcely any published study of the egg-laying or other habits of the adult Oedemagena in relation to Rangifer arcticus arcticus, other than a few recent notes by Banfield (1951a: 31-32, fig. 17); but its behavior in relation to the Lapland Reindeer seems to be fairly well known, and it is summarized by Jacobi (1931: 245-246). In the case of the Reindeer, the fly's eggs are laid (during the summer) generally on the legs, belly, and tail region of the victim; the larvae, on hatching, bore through the skin, travel widely through the body, and finally (in the autumn) reach the place for further development--beneath the skin of the back on both sides of the vertebral column. Each one makes a breathing-hole through the skin, and uses this as an exit when leaving the host in the following June. Only the younger animals, from one to about four or five years old, are heavily infested; those still older are spared, possibly having learned to guard themselves better against the fly. Curiously enough, the fawns are said to escape this parasitism entirely.

My own observations on the larvae were restricted to a few Caribou specimens in June and in the autumn. As with the Reindeer, the Caribou fawns in their first autumn showed no visible infestation, as I noted in looking over some fresh hides on September 10, and as was noted again in a fawn of September 26. Fred Schweder, Jr., made the remark that larvae would be evident in the fawns by the following spring; this may indicate that the larvae have not, in the autumn, completed their journey to their final position on the Caribou's back. I learned of no immunity on the part of old adults.

Fullgrown larvae still remained in bucks secured on June 3 (fig. 17) and 18. According to Charles Schweder, they drop out in June. In the buck of June 3 there were perhaps several dozen warbles, each surrounded by a mass of repulsive tissue; in another buck of June 18, there were apparently more than 75. "It may be assumed," says Johansen (1921: 24), "that the pupae lie on the ground for about a month before the flies appear." He found (1921: 29) the adult flies abroad at Dolphin and Union Strait by July 14.

In a buck of August 17 the new warbles (or perhaps merely warble scars from the previous June--cf. Banfield, 1951a: 32) on the inside of the skin were not very numerous. Some were medium-sized, but most were so small that it was not deemed necessary to scrape them off; they had comparatively little fatty tissue about them and were merely allowed to dry up. The number of warbles (or warble scars) found in autumn specimens varied considerably, up to a maximum of roughly 200. They were situated mostly along the mid-dorsum, and more on the lower back or rump than farther forward. The number appeared to be approximately 130 in the skin of an adult doe that was nailed to the log wall of a cabin for drying on September 15 (fig. 18). A doe of September 21 seemed to have less than the usual number of warbles.

The nostril fly (Cephenemyia) is another serious dipterous parasite of the Caribou. The life history of the European C. nasalis (L.) (or C. trompe [L.]) and its effect on Reindeer are discussed by Bergman (1917), Natvig (1918), and Jacobi (1931: 245) as follows.

This fly attacks the host from June to September, depositing its viviparous larvae in the nostrils. The Reindeer attempts to fend off the fly, striking at it with its hoofs and keeping its nostrils closed as far as possible. Once deposited, the lively larvae crawl into the inner nasal passages and as far as the larynx, where they fasten themselves and live on the mucus. A Reindeer may harbor as many as 130 of these parasites. They range from 6 to 26 mm. in length. Their particular growth begins at the end of March, and they are ready for pupation up to May. The host assists their exit by continual sneezing and snuffling. In the last stages they are a great affliction for the host, and they sometimes cause its death. Pupation takes place in or on the ground, under some sort of cover, and it lasts for 15-19 days. The flies have been found emerging from July 12 to 31.

The corresponding parasite of the Barren Ground Caribou is a similar or perhaps identical species, with a parallel life history. Its chief activity as an adult doubtless occurs in July and August. A number of the mature larvae were found in the throat of the buck of June 3; two of them that were preserved measure approximately 7 mm. in diameter and 27 and 30 mm. in length. A large mass of such sizable parasites in the throat might easily become a serious obstacle to comfortable living or even to survival on the part of the host. Presumably the larvae drop to the ground at about the same period as those of Oedemagena. Fred Schweder, Jr., remarked concerning the buck of August 17 that these larvae are never found at that season, and Charles Schweder made the same remark concerning a doe specimen of September 21. It would appear either that they remain so small as to escape detection at this time or that they do not reach the throat on their short journey from the nostrils until some later period of the year. Johansen (1921: 24) records larvae only 2-3 mm. long in the nasal passage at the end of May.

Since the bulk of the Caribou population has passed well to the northward of the Nueltin Lake region by the time the larvae of Oedemagena and Cephenemyia drop out of the bodies of their hosts to pupate briefly on or in the ground (say in the latter part of June), one is tempted to speculate on the possibility that the adult flies found here in August may have followed their prospective victims for many miles in their southward migration. However, Porsild remarks (1943: 386) that they "apparently do not travel very far."

Certain kinds of behavior exhibited by the Caribou in attempting to fend off the parasitic flies are discussed in the section on Shaking off moisture and insects.

The adults of Oedemagena tarandi (L.) were determined by Mr. C. W. Sabrosky, of the Bureau of Entomology and Plant Quarantine; and the larvae of Oedemagena and Cephenemyia by Dr. W. W. Wirth, of the same bureau. The larvae of the latter genus are regarded as probably C. trompe (L.); they were new to the collection of the United States National Museum.

References.--Hearne, 1795: 197; Franklin, 1823: 241; Richardson, "1825": 328-330, and 1829: 242; Godman, 1831, +2+: 284; Murray, 1858: 210; B. R. Ross, 1861: 438; Pike, 1917 (1892): 58-59; J. B. Tyrrell, 1892: 128, and 1894: 442; Whitney, 1896: 239; Russell, 1898: 228-229; Jones, 1899: 411; Hanbury, 1900: 67, and 1904: 32, 137, 194; Preble, 1902: 41; R. M. Anderson, 1913b: 504; Stefánsson, 1913b: 204, 212-213, 333; Douglas, 1914: 191-192; Malloch, 1919: 55-56; Hewitt, 1921: 67; Johansen, 1921: 22-24, 29, 35, 37; Stefánsson, 1921: 247; Blanchet, 1925: 32, and 1926b: 47; Birket-Smith, 1929 (1): 56, 133; Seton, 1929, +3+: 109-111; Critchell-Bullock, 1930: 193; Hoare, 1930: 33, 37-38; Kitto, 1930: 89; Jacobi, 1931: 244-245; Munn, 1932: 58; Sutton and Hamilton, 1932: 84-86; Birket-Smith, 1933: 90, 92; Ingstad, 1933: 48, 135; Hornby, 1934: 105; Soper, 1936: 429; Henriksen, 1937: 25, 26; Hamilton, 1939: 247, 301; Murie, 1939: 245; Clarke, 1940: 70, 95; Downes, 1943: 226, 255; Manning, 1943a: 53; Porsild, 1943: 386; Gavin, 1945: 228; Harper, 1949: 228; Banfield, 1951a: 31-33; Barnett, 1954: 104.

Ectoparasites

It was in vain that I searched a number of fresh specimens for lice, mites, fleas, or ticks. The Schweder boys spoke of never having noticed any such parasites. Seton (1929) mentions none, and Jacobi (1931: 243) records only a louse (Linognathus tarandi) from the Reindeer. "Lice are not known from caribou according to Ferris (in conversation)" (Weber, 1950: 154).

Relations to Reindeer

Recent discussions of the possibility or advisability of introducing domesticated Reindeer to replace, or to augment the diminishing supply of, native American Caribou in various new localities prompt a brief review of the subject.

It may be remarked at the outset that acclimatization attempts in the Old World have generally been abortive. Wild Reindeer introduced from Finmark into Iceland in the eighteenth century flourished for a time, but by 1917 they were almost exterminated. A number of different introductions into Great Britain, Denmark, Germany, Austria, Switzerland, and Italy came to naught. On the other hand, the introduction of Lapland Reindeer on the subantarctic island of South Georgia in 1908 seems to have turned out successfully. (Jacobi, 1931: 158-165; Harper, 1945: 473-474.) A saving feature in each of the above-mentioned cases was the absence of any native Reindeer whose racial purity might have been destroyed by the newcomers.