| Abstract: | Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarked and released in 52 broods. Another 141 ducklings were radiomarked at 4 weeks of age. Survival was estimated with the Kaplan-Meier nonparametric estimator and the Weibull parametric model. Most mortalities occurred within 10 days after hatch. Total brood loss occurred in 18 (35%) of 52 broods released. The primary sources of mortality were predation, principally by mink (Mustela vison), and exposure to precipitation and cold temperature. For combined years, females had lower survival than males (P = 0.03). If the disparate survival between sexes of canvasbacks observed in this study is representative of canvasbacks in their breeding range, this phenomenon contributes to reduced reproductive potential and the male-biased sex ratio of the species. |
| Genre: | Article |
| ProdID: | 1001159 |
| Citation Author: | Korschgen, C. E.; Kenow, K. P.; Green, W. L.; Johnson, D. H. |
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| Citation End Page: | 132 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Wildlife Management |
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| Citation Number Of Pages: | 12 |
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| Citation Phsyical Description: | p. 120-132 |
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| Citation Search Results Text: | Survival of radiomarked canvasback ducklings in northwestern Minnesota; 1996; Article; Journal; Journal of Wildlife Management; Korschgen, C. E.; Kenow, K. P.; Green, W. L.; Johnson, D. H. |
| Citation Start Page: | 120 |
| Citation Volume: | 60 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | Survival of radiomarked canvasback ducklings in northwestern Minnesota; 1996; Article; Journal; Journal of Wildlife Management; Korschgen, C. E.; Kenow, K. P.; Green, W. L.; Johnson, D. H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DOCUMENT): | http://www.npwrc.usgs.gov/resource/birds/radiomrk/index.htm |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
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