. The Ecology of arboreal folivores : a symposium held at the Conservation and Research Center, National Zoological Park, Smithsonian Institution, May 29-31, 1975 . Figure 6. Seasonal home range of each animal. tracking period, the means of the seasonal and annual ranges, and the 2-year ranges, all measured by the modified minimum-area method. Although the limitations of tracking on only 3 successive nights each month are recognized, the in- crease in area occupied by the animals with increasing time is evident, being on the average 270 percent from 1 night to 3 nights, 147 percent from 3 nigh
. The Ecology of arboreal folivores : a symposium held at the Conservation and Research Center, National Zoological Park, Smithsonian Institution, May 29-31, 1975 . Figure 6. Seasonal home range of each animal. tracking period, the means of the seasonal and annual ranges, and the 2-year ranges, all measured by the modified minimum-area method. Although the limitations of tracking on only 3 successive nights each month are recognized, the in- crease in area occupied by the animals with increasing time is evident, being on the average 270 percent from 1 night to 3 nights, 147 percent from 3 nights to a season, and 153 percent from a season to a year. The animals' 2-year ranges were on average 116 percent greater than their annual ranges. The increases probably result from the changing use of the home range as the opossums moved to meet their requirements. To illustrate this, shifts in monthly (3 night) centers of activity are shown joined consecutively in Figures 5a and 5b. To compare the distance of these shifts with the home-range size, a circle equal in area to the mean nightly range of each animal for each year determined on dry nights only is described about the geometric center of activity of the respective annual range. Seasonal and annual ranges In calculating the size of the seasonal ranges (Figure 6), all nights were included, wet or fine. The size of 9 293's range did not vary much between seasons, but was much smaller from the winter of 1971 on- ward, while the ranges of the other female and of C329 varied considerably between seasons. Male 291 showed the most pronounced changes, with dis- tinct peaks in autumn 1971 and summer 1971-72. The annual and cumulative 2-year ranges were measured by 3 methods: the modified minimum area, the minimum area, and the range length/range width method (Table 6). Figure 7 shows the annual ranges of each animal measured by the first method and their den sites. Comparing these areas between the first and second year, 9 144 s
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Keywords: ., bookcentury1900, bookcolle, booksubjectleaves, booksubjectmammals
