Survival of hatching-year female canvasbacks wintering on Chesapeake Bay
Journal of Wildlife Management
By: G. M. Haramis, Dennis G. Jorde, and C. M. Bunck
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Abstract
Low annual survival of hatching-year (HY) females is a critical management concern for canvasbacks (Aythya valisineria), and may contribute substantially to reduced reproductive potential and the male-biased sex ratio of the species. To evaluate the contribution of mortality on a traditional wintering area to low annual survival, we estimated survival rates of HY female canvasbacks during 3 winters (1987-89) on Chesapeake Bay. We implanted radio transmitters in 204 HY and 44 after-hatching-year (AHY; 1989 only) female canvasbacks and tracked them from mid-December to early March. Ten-week survival rates did not differ (P > 0.05) among years for HY females; estimates ranged from 0.833 to 0.930 and averaged 0.887. Of 17 mortalities recorded for HY females during the 3-year study, 14 of 15 dated deaths occurred during the duck hunting season (first 3 weeks of the study), even though the hunting season on canvasbacks was closed. As a result, survival rates were lower during hunting versus posthunting periods (P 5 0.05 for 2 of 3 yr). Illegal hunting was the single largest source of mortality for HY females. Shot ducks accounted for a loss of 4% and suspected crippling losses (ducks scavenged by shoreline predators) may have increased hunting-associated losses to as high as 7%. In 1989, no deaths were observed for AHY females, and their survival was higher (P = 0.02) than HY females. High winter survival for HY females indicates that substantial mortality occurs at some other time of the annual cycle.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Survival of hatching-year female canvasbacks wintering on Chesapeake Bay |
| Series title | Journal of Wildlife Management |
| Volume | 57 |
| Issue | 4 |
| Year Published | 1993 |
| Language | English |
| Contributing office(s) | Patuxent Wildlife Research Center |
| Description | 763-771 |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Journal of Wildlife Management |
| First page | 763 |
| Last page | 771 |
| Google Analytic Metrics | Metrics page |