Resource selection, survival, and departure of adult female mallards from the Lake St. Clair region during autumn and winter / Matthew Palumbo.

Includes bibliographical references.

During autumn and winter, mallards (Anas platyrhynchos) maximize fitness through their
spatiotemporal distribution to avoid mortality risks while balancing trade-offs to access foods
to undergo migration and maintain homeostasis. Thousands of mallards use Lake St. Clair as
it is an important, but threatened, migratory staging area in the Great Lakes. My goal was to
understand how mallards were selecting resources in the region and potential relationships of
selection strategies. My objectives were to estimate resource selection of adult female
mallards, in relation to perceived risk of hunting mortality, and determine if selection
strategies were related to survival and timing of departure. At Lake St. Clair, I equipped 59
adult female mallards with GPS back-pack transmitters to monitor resource selection and
movements from 27 August to 31 January 2014–15 and 2015–16. I used discrete-choice
modeling to determine if mallard resource selection strategies were best explained by
composition of habitat type (i.e., quality) and ownership type (i.e., presumed level of
mortality risk). I observed selection for habitat types managed by the Canadian Wildlife
Service, private landowners, and Michigan Department of Natural Resources throughout the
monitoring period. I classified these habitat types as low to moderate mortality risk. The area
of public water was selected for prior to and after the hunting season and classified as high
mortality risk, suggesting that disturbances and mortality risks from hunting could have
influenced selection. I used time-to-event analysis to determine how diurnal selection
estimates were related to mortality risk and probability of regional departure. As mallards
selected public water, mortality risk decreased during the non-hunting season, but increased
during the first half of the hunting season. Probability of departure decreased with selection
for public water across the second half of the hunting season and post hunting season.
Selection for Walpole Island water was related to an increase in mortality risk and departure
probability across seasons. As mallards selected for private water, departure probability
decreased during the second half of the hunting season, but increased during the post hunting
season. My research describes how mallards select resources in a heterogeneous landscape of
resources and risks.