Spinning-wing decoys are strong attractants to ducks and increase kill rates over traditional decoying methods. However, it is unknown whether all duck species are attracted similarly to ...spinning-wing decoys and whether the effectiveness of these decoys changes with latitude. We examined the effectiveness of spinning-wing decoys for 9 species of dabbling ducks during 545 experimental hunts in California (1999–2000), Minnesota (2002), Manitoba (2001–2002), Nebraska (2000–2002), Missouri (2000–2001), and Arkansas (2001–2003). During each experimental hunt, we systematically alternated between 2 paired decoy treatments every 15–30 min (depending on study site): traditional decoys only and traditional decoys with a spinning-wing decoy. Overall, 70.2% (n = 1,925) of dabbling ducks were harvested (shot and retrieved) when spinning-wing decoys were turned on, ranging from 63.6% (n = 187) in Missouri to 76.4% (n = 356) in Minnesota. Effectiveness of spinning-wing decoys increased with latitude of study sites. Proportions of ducks shot when spinning-wing decoys were turned on differed among species, from a low of 50.0% (n = 8) for cinnamon teal (Anas cyanoptera) to a high of 79.0% (n = 119) for American wigeon (A. americana). The probability of being shot when spinning-wing decoys were turned on increased with annual survival rates among species; for example, spinning-wing decoys were more effective for American wigeon and mallard (A. platyrhynchos) than they were for cinnamon teal and American green-winged teal (A. crecca). Effectiveness of spinning-wing decoys did not differ consistently by age or sex of harvested ducks. Our results indicate that the effectiveness of spinning-wing decoys differs among duck species and changes with latitude; thus, consideration of these effects may be warranted when setting harvest regulations and methods of take.
Many species of waterfowl are capable of breeding as yearlings. A nine-year study of the demographics and ecology of Giant Canada Geese in central Missouri provided an opportunity to monitor the ...incidence and success of nesting attempts by yearling males and females in a local population that was established by translocation of wild geese 20 years ago.
True Metabolizable Energy of Moist-Soil Seeds Checkett, J. Michael; Drobney, Ronald D.; Petrie, Mark J. ...
Wildlife Society bulletin,
12/2002, Letnik:
30, Številka:
4
Journal Article
Habitat objectives for migrating and wintering waterfowl are often established by converting population energy demands into an equivalent measure of foraging habitat. In some areas, seeds produced ...from moist-soil plants provide a significant proportion of the energy available to waterfowl. To accurately establish habitat objectives for migrating and wintering waterfowl, managers must estimate seed production from moist-soil plants and have information on metabolizable energy (ME) of moist-soil seeds. Although methods for estimating seed production have been developed, ME has been determined for few natural seeds. We determined true metabolizable energy (TME) of 10 moist-soil seeds commonly consumed by wintering and migrating ducks. TME estimates were similar (P>0.05) for hairy crabgrass (Digitaria sanguinalis; 3.09 kcal/g), little hairy crabgrass (D. ischaemum; 3.10 kcal/g), pigweed (Amaranthus spp.; 2.97 kcal/g), yellow foxtail (Setaria lutescens; 2.88 kcal/g), fall panicum (Panicum dichotomiflorum; 2.75 kcal/g), curly dock (Rumex crispus; 2.68 kcal/g), and wild millet (Echinochloa crusgalli; 2.61 kcal/g), but less (P<0.05) for beakrush (Rynchospora corniculata; 1.86 kcal/g), paspalum (Paspalum laeve; 1.57 kcal/g), and nodding or curltop ladysthumb smartweed (Polygonum lapathifolium; 1.52 kcal/g). TME values determined for moist-soil seeds in this study will allow managers to accurately estimate carrying capacity of waterfowl habitats.
Recent years
have witnessed a major transformation in public policy that has significant
ramifications for health care professions. Through a process known as
devolution, the federal government has ...shifted major amounts of money and
decision-making authority to state governments. In health care, this shift
places resources closer to the local levels, where practitioners have
opportunities to influence their use. Varying perspectives on devolution are
presented by 4 experts in state and local government to suggest some possible
ways that professional psychology can become more involved in this process.
We observed an apparent incident of polygynous behavior in Giant Canada Geese (Branta canadensis maxima). Two females were paired with the same male and concurrently incubated side by side within the ...same nest tub. Reciprocal changes in the number of eggs within each bowl during incubation indicated that eggs were shifted between nest bowls in both years. This behavior was observed at the same location in two successive years. Goslings hatched from both nests each year. Polygynous behavior in typically monogamous Canada Geese has rarely been observed, and nest sharing has not been previously documented.
