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Survival of Gadwall and Mallard Ducklings in Southcentral Saskatchewan
Michel Gendron and Robert G. Clark
The Journal of Wildlife Management
Vol. 66, No. 1 (Jan., 2002), pp. 170-180
Stable URL: http://www.jstor.org/stable/3802883
Page Count: 11
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Recent studies have reported considerable spatiotemporal variation in duckling survival. Using radiotelemetry, we monitored 114 mallard (Anas platyrhynchos) and 73 gadwall (A. strepera) brood-rearing females on St. Denis National Wildlife Area (SDNWA), Saskatchewan, Canada, during 1996 and 1997 and at Allan Hills (AH), Saskatchewan, Canada, during 1997 to (1) determine duckling survival, and (2) evaluate several hypotheses advanced to explain variation in survival. Overall, gadwall duckling survival to 30 days was greater than that of mallard ducklings. Additionally, initial brood size of gadwall was greater than mallard on SDNWA during 1996 and at AH during 1997; no difference was detected on SDNWA during 1997. When effects of initial brood size and duckling survival were combined, gadwalls typically produced more ducklings than mallards during all years and at all sites. Relative to previous studies, high survival rates and little variation in survival between years or study sites (1997), or with hatching date (both species), probably resulted from excellent wetland habitat conditions. Some studies have reported lower survival in broods that traveled farther overland to wetlands, but little support was obtained for this hypothesis. Likewise, no consistent intraspecific patterns existed between duckling survival and initial brood size, or indices of female body size and condition.
The Journal of Wildlife Management © 2002 Wiley