Shot prevalences and diets of diving ducks five years after ban on use of lead shotshells at Catahoula Lake, Louisiana
Journal of Wildlife Management
By: J.L. Moore, W.L. Hohman, T.M. Stark, and G.A. Weisbrich
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Abstract
Catahoula Lake, central Louisiana, is a RAMSAR Convention Wetland of International Importance and among the most important wintering and staging areas for waterfowl in North America. To evaluate exposure rates in Catahoula Lake waterfowl 5 years after a ban on use of lead shot, we determined the prevalence of ingested shot and diets of canvasbacks (Aytliya valisincria) and lesser scaup (A. ajfinis) salvaged from commercial fishing nets in winter 1992-93. Plant material composed >77% of the midwinter diet of canvasbacks. Consumption of belowground plant material (e.g., chufa flatsedge [Cypcrus cscttlenttis] and arrowhead [Sagittaria spp.] tubers) exceeded 47% in 1992-93, but was lower than in 1987-88. Male lesser scaup fed almost exclusively on plant material, especially bearded sprangletop (Lcptochloa fascictilaris) and millet (Echinochloa spp.). Prevalence of ingested lead or steel shot was similar in canvasbacks (38%) and lesser scaup (34%) in spite of differences in foraging behavior, suggesting that ducks actively selected shot as grit. Shot (lead or steel) prevalence in diving ducks at Catahoula Lake was similar in winters 1987-88 and 1992-93, but the proportion of birds with lead in their gizzards was greatly reduced in 1992-93 (6%) compared to 1987-88 (27%). Because ingestion of lead shot deposited in wetlands prior to steel shot regulations remains a problem at some sites, we suggest that provision of nontoxic grit may serve to reduce lead shot prevalence in waterfowl at contaminated sites.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Shot prevalences and diets of diving ducks five years after ban on use of lead shotshells at Catahoula Lake, Louisiana |
| Series title | Journal of Wildlife Management |
| Volume | 62 |
| Issue | 2 SUPPL. |
| Year Published | 1998 |
| Language | English |
| Publisher | Wildlife Society |
| Contributing office(s) | National Wetlands Research Center, Wetland and Aquatic Research Center |
| Description | 6 p. |
| First page | 564 |
| Last page | 569 |
| Country | United States |
| State | Louisiana |
| Other Geospatial | Catahoula Lake |
| Google Analytic Metrics | Metrics page |