. The Canadian field-naturalist. 110 The Canadian Field-Naturalist Vol. 85. Figure 5. Pneumonia-lungworm disease in a bighorn sheep ewe in Kootenay National Park, October 1966. Note lumps on lungs infested with pneumonia-lungworm organisms, which convert these areas to a hepatized appearance. sheep died (Superintendent of Waterton annual report 1937). However, since the population estimate 10 years later was only 125, losses throughout 1937 must have exceded 75% (Banfield 1947). Annual reports of the park for the intervening period showed steady popu- lation increases. The second die-off occur
. The Canadian field-naturalist. 110 The Canadian Field-Naturalist Vol. 85. Figure 5. Pneumonia-lungworm disease in a bighorn sheep ewe in Kootenay National Park, October 1966. Note lumps on lungs infested with pneumonia-lungworm organisms, which convert these areas to a hepatized appearance. sheep died (Superintendent of Waterton annual report 1937). However, since the population estimate 10 years later was only 125, losses throughout 1937 must have exceded 75% (Banfield 1947). Annual reports of the park for the intervening period showed steady popu- lation increases. The second die-off occurred in Kootenay in the fall and winter of 1940-41, when an esti- mated 120 animals (85%) died of verminous pneumonia (Cowan 1943). The 1938 popula- tion was estimated at 140 by Cowan (1943). The third die-off occurred in Banff in 1941- 42. The count by the warden was only 241 in 1942, while the maximum total was 500 in 1943 (Cowan 1943). Numbers continued to decline until they reached 351 in 1950 (Tanner 1950). Green (1949) cited the following examples of population declines throughout Banff park: 1. Sawback — Vermilion range — 300-400 sheep some 20 years previously (1929); the highest count was 147 from 1942 to 1948 progressively declining from 1942. 2. Palhser range — 600-700 sheep in the sum- mer of 1927 or 1928; the highest count was 43 from 1942 to 1948. 3. South of the Bow River, presumably on the Goat Range, 100 sheep in 1914; no sheep from 1942 to 1948. The fourth major die-off occurred on pro- vincial lands east of the parks. In 1945, bighorns were reported dying from an infectious lungworm disease in the Livingstone-Highwood range (Huestis 1946). Numbers generally de- clined throughout south-western Alberta during. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club
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