Landscape-level correlates of mallard duckling survival : implications for conservation programs / Pauline M. Bloom, Robert G. Clark, David W. Howerter, and Llwellyn M. Armstrong.

Includes bibliographical references (pages 822-823).

Despite recent work, uncertainty remains concerning how abiotic and biotic factors affect
duckling survival. Additionally, upland habitat characteristics may affect duckling survival rates but this
potential relationship has largely been ignored. We evaluated several unresolved hypotheses about causes of
mallard (Anas platyrhynchos) duckling survival variation, with an emphasis on assessing effects of managed
and remnant natural upland habitats. During 1993–2000, 617 radio-marked females provided information
about brood habitat use and duckling survival on 27 sites in prairie Canada. We contrasted a priori and
exploratory models that incorporated effects of upland, wetland, weather, female, and brood-related variables
on duckling survival rates. Survival was highest for ducklings when a greater proportion of their surrounding
landscape (i.e., within a 500-m radius buffer around the brood) was comprised of wetlands characterized by a
central expanse of open water and a peripheral ring of flooded emergent vegetation. Cold and wet weather in
the first week of life resulted in lower duckling survival. In a post hoc analysis, duckling survival (of older
ducklings) was negatively related to increasing proportions of managed hayland.