Data and Model-based Estimates from Black Brant (Branta bernicla nigricans) Fall Age Ratio Surveys at Izembek Lagoon, Alaska

These data are in three tables relating to fall age ratios (number of juvenile birds : total birds aged) of Black Brant (Branta bernicla nigricans) staging in Izembek Lagoon, Alaska, since 1963. The first table is observation data for the age classes of Black Brant during surveys, and associated survey characteristics. Two tables provide model-based estimates of age ratios by year along with Standard Error (SE), and 95% Bayesian credible intervals around estimates. One table ("baseModel") does not distiguish observer vantage point (land or boat), the other does ("vantageModel").