Kevin P. Kenow William L. Green Douglas H. Johnson Michael D. Samuel Louis Sileo Carl E. Korschgen 1996 <p>Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (<i>Aythya valisineria</i>). 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 <span>≥</span> to 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 (85%) of 52 broods released. The primary sources of mortality were predation principally by mink (<i>Mustela vison</i>), and exposure to precipitation and cold temperature. For combined years, females had lower survival than males (<i>P</i>=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.</p> application/pdf 10.2307/3802046 en Wiley Survival of radiomarked canvasback ducklings in northwestern Minnesota article