NPWRC :: Predictable Interregional Movements by Female Northern Pintails During Winter

PRIMARY STUDY AREA covers SW corner of Louisiana; EXTENDED SEARCH AREA covers southeastern Texas, central Louisiana, western Mississippi, eastern Arkansas, and the SW corner of Tennessee; GULF COAST AREA extends from SE Texas to the southern tip of Alabama; MISSISSIPPI ALLUVIAL VALLEY covers the Mississippi River extended from the southern tip of Illinois down through Louisiana

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).

Figure 2 - Three line graphs illustrating Retention Rate during the winters of 1990-91, 1991-92, 1992-93

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.

Figure 3 - Three maps of the Mississippi Valley and Gulf Coastal states illustrating the locations of 152 radiotagged Northern Pintails during the three years of the study

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).

Figure 4 - Two line graphs showing % of Flyway for Louisiana and Arkansas; Fitted regression line for Louisiana starts at >100% and ends at approx. 75%; Fitted regression line for Arkansas starts at 0% and ends at approx. 25%

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.

Figure 5 - Map of Mississippi Valley and Gulf Coastal states showing locations of radiotagged Northern Pintails in relation to amount of land area (by county) planted in rice

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.


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Predictable Interregional Movements by Female Northern Pintails During Winter

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