Survival of hatching-year female canvasbacks wintering on Chesapeake Bay

Journal of Wildlife Management
By: , and 

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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.

Additional publication details

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