. The Canadian field-naturalist. 1980 Fisher and Myres: Clark's Nutcracker in Canada 47 NOV 8/72. Figure 3. Annual distribution of extralimital occurrences of Clark's Nutcracker from August to November only (1960-1976) for each province, showing certain syn- chronies and regularities between provinces (see text). The number above each column refers to the number of individuals. b) In 1976 the western prairie regions had a wet August with subnormal temperatures. Low pressure systems with thunderstorms and showers passed across southern Alberta and northern Montana on 16, 23, and 25 August. At v
. The Canadian field-naturalist. 1980 Fisher and Myres: Clark's Nutcracker in Canada 47 NOV 8/72. Figure 3. Annual distribution of extralimital occurrences of Clark's Nutcracker from August to November only (1960-1976) for each province, showing certain syn- chronies and regularities between provinces (see text). The number above each column refers to the number of individuals. b) In 1976 the western prairie regions had a wet August with subnormal temperatures. Low pressure systems with thunderstorms and showers passed across southern Alberta and northern Montana on 16, 23, and 25 August. At various times during this period winds were from the southwest (from Montana) ahead of southward-moving cold fronts. During this period flocks of nutcrackers were reported in the Cypress Hills, Alberta (Fisher 1979) (Table 1). Discussion In studying bird dispersal over vast regions, records of amateur field-naturalists are invaluable. Because Clark's Nutcrackers are conspicuous and because the observations analyzed here are only from locations outside the normal range of the species, the annual number of observations provides a fairly reliable Figure 4. (Top). Weather chart showing the position of low pressure systems one day prior to the first extralimital occurrence of a Clark's Nutcracker (four-point star) in Ontario on 9 November 1972. (Bottom). Weather chart for the day of the first two extralimital occur- rences of nutcrackers near Vancouver(British Colum- bia), just prior to several occurrences in central Alberta and the second extralimital occurrence in Ontario, on 14 November 1972. Stippling indicates precipitation. Four-point stars indicate one or more extralimital occurrences of Clark's Nutcracker. index to the distribution and magnitude of dispersal movements. The number of reports from the Edmon- ton area in November of 1972 was probably increased by newspaper publicity (R. Lister, personal communication).. Please note that these images are extracted from scanned pa
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