The Canadian field-naturalist (1973) (20511827812)

Title: The Canadian field-naturalist
Identifier: canadianfieldnat1973otta (find matches)
Year: 1973 (1970s)
Authors: Ottawa Field-Naturalists' Club
Subjects:
Publisher: Ottawa, Ottawa Field-Naturalists' Club
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library



Text Appearing Before Image:
1973 Demarchi and Mitchell: The Chilcotin River Bighorn Population 447
Text Appearing After Image:
Figure 8. Relict Slope area. The ridges in the foreground are utilized as bedding areas for rams, the gentle slopes are used by ewes and rams as feeding grounds and as a rutting area. of the Farwell Canyon band. Also, these same terraces could be used by the Farwell Canyon band as the rutting area. Classified counts conducted in August 1968 located 182 ewes and yearhngs and 76 lambs. Both figures represent the highest number of animals counted during the series of surveys (Table 4). By November 1968 only 143 ewes and yearlings and 33 lambs could be located. The March 1969 count revealed 13 fewer ewes and yearlings. Censuses conducted in August and December 1969 and September 1970 located 112, 121, and 125 ewes and yearlings, respectively. These consistently low counts in- dicate that a die-off had occurred in the winter of 1968-1969. The number of lambs counted in the same period was lower than in August 1968 but the proportion of lambs per 100 ewes remained about the same, between 37 and 46 (Table 5). Ground counts conducted on a hmited por- tion of the range on animals of the Junction and Relict Slope bands during the lambing periods indicated high ratios of lambs to 100 ewes. In May 1964, 218 animals were classi- fied, indicating a ratio of 77 lambs per 100 ewes. In June 1968, 179 animals were classi- fied, indicating a ratio of 62 lambs per 100 ewes. The sample sizes for these two early season counts were very large, but many ewes without lambs were obviously missed as a late July 1968 count of 186 ewes and lambs indi- cated 50 lambs per 100 ewes, while a more extensive search with a helicopter in the same