Abstracts

Presented by Chris Nicolai - Email: chris_nicolai@fws.gov

Geolocators are a relatively new, small, and cheap technology that uses light levels to assess animal movements and behavior, but have received little attention for waterfowl studies. We attached geolocators on wood ducks, mallards, and canvasbacks from 2014 through 2017. Geolocators are typically mounted on legbands or backpacks for birds, but we also fitted waterfowl with nasal saddle mounts as we were originally concerned with the recording of light levels on legbands. We used both recaptures and hunter kills to retrieve geolocators. For wood ducks, we marked both confirmed nest box breeders and birds with no history of nest box use. We were able to develop Bayesian mixture models to assign light levels to breeding behaviors for both nest box and natural cavity breeding birds to assess nest success for birds which survived until geolocators could be retrieved. We were able to designate each day as either nesting or non-nesting from geolocator data, enabling estimation of life-history traits such as nesting propensity, annual nesting attempts, incubation duration and nest success. We also attempted to distinguish among nest prospecting, laying, incubation, and brood-rearing behaviors using an unsupervised time-series clustering algorithm, and to further estimate clutch size and nest fate. Using artificial nest box monitoring as validation data, we confirmed the accuracy of geolocator-derived estimates of the number and timing of nesting attempts and nest success. For canvasbacks, we retrieved a total of 8 geolocator devices which provided >9 months of movement and breeding propensity data. All females showed evidence of breeding in areas of either Alaska or prairie Canada. Three males used the Canadian prairies in the summer and one used southwestern Alaska. Our data was sufficient to show both rapid and slow movements across seasonal areas of use and provides information on movements for pacific flyway canvasbacks.