Predictable Interregional Movements by Female Northern Pintails During Winter
Figures
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Figure 1. Primary study area (short-dashed polygon),
with Lacassine Pool in the center, and extended search area (long-dashed
polygon) in which radiotagged female Northern Pintails were tracked
during winters 1990-1991 through 1992-1993. Regions include Gulf
Coast (dark shading; Chabreck et al. 1989; Stutzenbaker and Weller
1989), Mississippi Alluvial Valley (light shading; Reinecke et al.
1992), and Rice Prairie of southeastern Texas (horizontal hatches; Hobaugh
et al. 1989). |
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Figure 2. Retention rate (1 emigration
rate) during each winter for 347 female Northern Pintails radiotagged
in southwestern Louisiana. Sample sizes were 41 (29 adults; 12
immatures) during 1990-1991, 154 (96 adults; 58 immatures) during 1991-1992,
and 152 (108 adults; 44 immatures) during 1992-1993. Thin vertical
lines extending the length of Y-axes depict opening and closing of first
and second hunting seasons. Thick vertical bars at the bottom
of each plot represent days when weather was classified as stormy.
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Figure 3. Locations of 152 radiotagged female
Northern Pintails that emigrated from southwestern Louisiana during
winters 1990-1991 through 1992-1993. Plots represent 56
locations on 16 females during 1990-1991(top), 144 locations on
69 females during 1991-1992 (center), and 356 locations on 67
females during 1992-1993 (bottom). Dashed polygon represents
primary study area (see Fig. 1 for
delineation of extended search area). Regions include Gulf
Coast (dark shading; Chabreck et al. 1989; Stutzenbaker
and Weller 1989), Mississippi Alluvial Valley (light shading;
Reinecke et al. 1992), and Rice Prairie Region of southeastern
Texas (horizontal hatches; Hobaugh et al. 1989). |
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Figure 4. Percentage of Northern Pintails
in Mississippi Flyway observed in Louisiana and Arkansas during
mid-winter surveys (Y-axes) in relation to year (X-axes) during
1980-1995. Fitted regression lines and equations are from
models including 1991. |
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Figure 5. Locations of radiotagged female Northern
Pintails that emigrated from southwestern Louisiana during winters 1990-1991
through 1992-1993 in relation to 4 levels of land area (ha) planted
in rice in each county or parish during 1992 (National Agricultural
Statistics Service). Plot represents 556 observations on 152 females. |