Survival, Harvest, and Lincoln Estimates of Wood Ducks Banded in Ohio

Abstract

Abstract Wildlife agencies have carefully managed wood duck Aix sponsa populations in part through harvest regulations since the early 1900s. However, unlike many other waterfowl species in North America, waterfowl managers largely do not know breeding population size. Lincoln–Petersen methods based on harvest and band recovery data are an attractive alternative to air or ground count-based surveys for estimating populations of wood ducks by state and federal agencies that are tasked with sustainably managing harvest opportunities for this species. We used banding and recovery data to estimate annual survival rates, harvest rates, and population size in late summer (August–September) using Lincoln–Petersen methods for wood ducks banded within Ohio from 1990 to 2017. Sex, age, and daily bag limits best explained survival rates of wood ducks banded in Ohio, with lower survival rates in years with more liberal bag limits. Lincoln–Petersen estimates of population size ranged from 116,992 to 632,462 annually, and we detected a significant declining trend in population size through time. Mean harvest rates of wood ducks banded in Ohio ranged from 0.069 (adult females) to 0.121 (hatch-year males), and we detected a significant increasing trend in harvest rate through time for adult male, hatch-year male, and hatch-year female wood duck cohorts. Aerial surveys in other Great Lakes states provide comparable population estimates with our Lincoln–Petersen estimates for Ohio and also show a declining trend in population size. We recommend continued investigation into the use of Lincoln–Petersen techniques for estimating wood duck population size throughout the Great Lakes region. If declining population trends are not unique to Ohio, waterfowl managers may need to further assess the potential impact of increased harvest rates on population size to ensure sustainable harvest into the future.