For such a distinct and regular feature in the life cycle of the species as the retrograde autumnal movement there must be some biological explanation. Several possible factors appear reasonably clear. Perhaps we may consider the Barren Grounds the true and preferred home of Rangifer arcticus, from which a proportion of the population is driven during part of the year under stress of insect attacks or shortage of food. When the animals begin to enter the woods in August, there is no shortage of food; thus an insect-induced frenzy may possibly be regarded as a potent force driving them southward. In September a state of comparative peace descends upon the caribou world: the current crop of adult insects has subsided; the larvae of warble and nostril flies have not attained the formidable size of the following spring and perhaps are not yet causing any severe discomfort; little or no snow covers up the food supply; the lakes and rivers, still unfrozen, offer a ready way of escape from pursuing Wolves; moderate or even balmy weather gives nature a pleasant mood. In short, both man and beast may well look upon early autumn as the very finest time of year both on the Barrens and in the adjacent wooded country.
Under these circumstances a definite retrograde movement out of the wooded country in September on the part of many Caribou must indicate their preference for the Barrens at this season. In any event, the movement begins just after the insect menace has subsided to a negligible stage. Possibly another inducement for retreating from the wooded country in the early fall is the dearth of open areas in which the animals may spend their resting periods, in comparative safety from Wolves. It is only after the freeze-up that the surfaces of the lakes and rivers supply this desideratum. This condition lasts from November to June—precisely that part of the year in which the Caribou are present in the wooded country in the greatest numbers.
But by November what are the conditions on the Barrens? The weather has become severe; snow has covered up a large part of the ground lichens; tree lichens are not to be had. And so at this season, with the coming of the first heavy snows, there is a final movement out of the Barrens into the shelter of the woods, leaving only a minority of the animals to face a bleak and bitter winter in the open country. The biggest herds of the year may then be seen passing southward. A few bucks are said to remain during most winters in the Windy River area.
Far to the westward, toward Great Slave and Great Bear lakes, the retrograde movements are somewhat different and more complicated (Clarke, 1940: 96).
“Mr. Carl Buchholz, of Churchill, describes the caribou migration at the 60th parallel, north of Churchill, as a southward migration in August, northward in September, and then south in the autumn” (Clarke, 1940: 97). (See also the next paragraph.)
[ Fall migration in the Churchill region]
The following notes for 1947 were kindly furnished me by Angus MacIver. He reported large numbers of Caribou moving southward across Caribou Creek (25 miles south of Churchill) about November 10, a day after the local freeze-up. He would then see thousands in a day. Prior to that time (perhaps in September?) there had been two “runs” to the northward and northwestward; these presumably represented the normal retrograde migration in the fall. The herds engaged in these two northerly movements must have previously passed southward farther inland. He reported also that the rutting season this year had commenced a little later than the usual October 15.
References on migration.—Dobbs, 1774: 20, 22; Hearne, 1795: 39, 40, 56, 66, 74, 85-87, 286, 299; Franklin, 1823: 241-242; Sabine, in Franklin, 1823: 667; Richardson, “1825”: 328-329, and 1829: 242-243; Godman, 1831, 2: 283-284; John Ross, 1835a: 328, 330, 337, 376, 390, 529-530, 628; J. C. Ross, in John Ross, 1835b: xvii; Richardson, in Back, 1836: 498; Simpson, 1843: 76, 196, 233, 277, 301, 320-321, 328, 386; Rae, 1850: 93; Richardson, 1852: 290, 296; Rae, 1852a: 79; J. Anderson, 1857: 326, 328; Murray, 1858: 203; Richardson, 1861: 274, 275; B. R. Ross, 1861: 438-439; Osborn, 1865: 223-224, 226; Kumlien, 1879: 54; R. Bell, 1881: 15C; Caton, 1881: 108; Gilder, 1881: 196-197; Nourse, 1884: 235, 356; Schwatka, 1885: 77-79, 83; Boas, 1888: 502; Collinson, 1889: 244, 290; Pike, 1917 (1892): 48-49, 50, 89-91, 101, 174, 204, 209, 220; J. B. Tyrrell, 1892: 128-130; Dowling, 1893: 103, 107; J. B. Tyrrell, 1894: 442, 1896: 13, 63, and 1897: 10, 19, 21, 49-50, 76, 124, 140, 142, 165; Russell, 1895: 48, and 1898: 88, 226; Whitney, 1896: 157, 238, 241; Lydekker, 1898: 48; J. W. Tyrrell, 1908 (1898): 77-78, 80; Jones, 1899: 368, 374; Hanbury, 1900: 66-67, 69, 71; A. J. Stone, 1900: 50, 53; W. J. McLean, 1901: 5, 6; Elliot, 1902: 259, 260, 274-275; Preble, 1902: 42; J. W. Tyrrell, 1924 (1902): 26, 31; Hanbury, 1904: 10, 30, 32, 34, 58, 93, 108, 120, 121, 139; Hornaday, 1904: 137; Stone and Cram, 1904: 52; MacFarlane, 1905: 683-685; J. A. Allen, 1908a: 490; Amundsen, 1908, 1: 97, 102-106, 200, 247, 326-329; Preble, 1908: 137-139; Cameron, 1912: 127; Wheeler, 1912: 199-200; R. M. Anderson, 1913a: 6, and 1913b: 502; Stefánsson, 1913a: 94-96, 99, 100, 103, 106, 1913b: 203-204, 224-225, 263-265, 269, 294, 348-350, and 1914: 39, 41, 54; Chambers, 1914: 93; Hornaday, 1914, 2: 101-104; Wheeler, 1914: 58; Harper, 1915: 160; Camsell, 1916: 21; Thompson, 1916: 99-101; Kindle, 1917: 107-108; Camsell and Malcolm, 1919: 46; Whittaker, 1919: 166-167; Buchanan, 1920: 105-108, 128-129; Hewitt, 1921: 60-63; Stefánsson, 1921: 401; Jenness, 1922: 15, 17, 25-26, 125; Blanchet, 1925: 32-34, and 1926b: 46-48; Mallet, 1926: 79; Preble, 1926: 137-138; Rasmussen, 1927: 54, 214-217, 246; Birket-Smith, 1929 (1): 51, 56, 101, 106; Seton, 1929, 3: 122, 125-128; Blanchet, 1930: 49-52; Critchell-Bullock, 1930: 58, 192-196; Hoare, 1930: 13, 14, 16, 21, 22, 27, 31, 33, 36-38; Kitto, 1930: 87; Mallet, 1930: 20-23, 27; Jacobi, 1931: 80-84, 192-210; Harper, 1932: 30, 31; Munn, 1932: 58; Sutton and Hamilton, 1932: 79, 81; Weyer, 1932: 40; Birket-Smith, 1933: 91-94, 112, 118; Ingstad, 1933: 34, 134-135, 156-159, 161, 163, 225, 229-231, 280, 291, 293, 296, 324; Weeks, 1933: 65; R. M. Anderson, 1934a: 81, 1937: 103, and 1938: 400; Hornby, 1934: 105-107; Birket-Smith, 1936: 91; Hamilton, 1939: 244-247, 359; Murie, 1939: 244; Clarke, 1940: 8-9, 11, 85-100; G. M. Allen, 1942: 298-299; Soper, 1942: 143; Downes, 1943: 215, 221, 224, 249, 250, 253-256, 260; Manning, 1943a: 52, and 1943b: 103; Porsild, 1943: 389; Soper, 1944: 248-249; Wright, 1944: 186, 190; Gavin, 1945: 227-228; R. M. Anderson, 1947: 178, and 1948: 15; Manning, 1948: 26-28; Rand, 1948a: 212, and 1948b: 149; Banfield, 1949: 478, 481; Harper, 1949: 226-230, 239-240; Banfield, 1951a: 6, 9-12, 28, and 1951b: 120; Anonymous, 1952: 267; Barnett, 1954: 96, 103.
[ Summation of Geographical Distribution]
The localities from which hitherto unpublished notes on Rangifer arcticus arcticus are presented in this paper include the following. Keewatin: Nueltin, Windy, “Highway” (at source of Putahow River), and Ennadai lakes; Little Dubawnt, Kazan, Red, Windy, Little, and Thlewiaza rivers; between Eskimo Point and Baker Lake. Manitoba: Nueltin (southern part), Nejanilini, Reindeer, and Split lakes; Seal River; Churchill; Cape Churchill; “Little Barrens” south of Churchill; between Churchill and Knife Lake; Caribou Creek, 25 miles south of Churchill. Saskatchewan: small lakes southwest of Reindeer Lake; lakes south of Lake Athabaska. Details as to occurrence and status in these localities are supplied on other pages.