Few studies have estimated reproductive and survival parameters of breeding ducks simultaneously, although such efforts can reveal relationships among vital rates. We estimated survival of mallard (Anas platyrhynchos) nests and ducklings on 8 study sites in south-central Saskatchewan during spring and summer 2000 and 2001. We observed a strong positive correlation between these parameters (r = 0.914) and through analysis of residual values found 14% of the relationship was explained by a predator-removal treatment, 26% by year effects, 44% by spatial variation, and 16% unexplained. Potential mechanisms include similar environmental factors influencing both parameters (e.g., predators) and positive density dependence. Information regarding covariation among vital rates is important in construction and interpretation of population growth models describing population dynamics of mallards and other upland-nesting ducks.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 71 • No. 5