Presented by John M. Eadie - Email: jmeadie@ucdavis.edu
Traditional methods to estimate survival, fidelity, and reproductive success of wood ducks typically involve analyses of banded females caught on the nest during incubation. Such analyses provide a strong foundation for management. However, might such analyses be incomplete or potentially biased? Females banded on the nest comprise only a subset that: initiate a nest, begin incubation, and do so for at least 1-3 weeks into incubation. This misses what may be a sizable fraction including: females that fail prior to capture, brood parasitic females that only lay eggs in other females nests, and young first-year recruits that prospect for nests but do not breed in their first year. Failure to include these females could lead to inaccurate estimates of several key demographic parameters. We followed 4 different populations of wood ducks in California since 1997 using traditional band capture/ recapture techniques. In 2014, we initiated studies to implant PIT tags in every female and all ducklings, install RFID readers on every nest box at each site, and genotype all females and ducklings at each population using 19 microsatellite markers. To date, we have amassed data comprising over 1,000,000 RFID reads on over 500 breeding females and over 5,000 PIT-tagged ducklings. Our emerging results provide unexpected insights, including: (1) females explore a wide variety nest sites, far exceeding the number based on band recapture patterns; (2) many females lay in multiple nests concurrently, and incubating females on a given nest may not be those that layed the most eggs in that nest; (3) many apparent non-breeders did in fact attempt to breed but failed, and we now can estimate how many and who those females are; and (4) a large number of females who survived, were present in the population, and were recorded on nests would have been missed entirely using traditional banding capture/recapture techniques. In addition, we recorded large numbers of ducklings that recruit, visit nest sites and sometimes laid eggs, but are never caught or banded. Our results suggest that previous analyses of wood duck demography may be missing several key components. New technologies such as PIT tagging may provide novel insight into important but under-studied population demographic processes.E.1-2: PIT-tagging and RFID Tracking Provide New (and Surprising) Insights on Nest Site Use, Fidelity, Female Survival and Recruitment of Wood Ducks in California
John M. Eadie, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA
Tez F. Stair, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA
Ami C. Olson, California Department of Fish and Wildlife, Sacramento, CA,
Bruce E. Lyon , Department Ecology and Evolutionary Biology, University of California, Santa Cruz, CA
Eli S. Bridge, Oklahoma Biological Survey, University of Oklahoma, Norman, OK
Tez F. Stair, Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA
Ami C. Olson, California Department of Fish and Wildlife, Sacramento, CA,
Bruce E. Lyon , Department Ecology and Evolutionary Biology, University of California, Santa Cruz, CA
Eli S. Bridge, Oklahoma Biological Survey, University of Oklahoma, Norman, OK