Effects of Liberalizing Harvest Regulations on Canada Goose Demography in Nebraska

Abstract

AbstractHarvest regulations are used to manage game species. Across their range, Canada geese Branta canadensis have recovered from near extirpation and are now perceived as overabundant and even a nuisance or a threat to human safety in many regions. Like many states, Nebraska has liberalized harvest regulations to increase recreation opportunities for consumptive users and to control increasing numbers of Canada geese. However, the efficacy of harvest regulations to control goose abundance is unclear. We used a live capture–recapture and dead recovery data set of more than 19,000 Canada geese banded in Nebraska 2006–2017 to determine the effect of liberalized harvest regulations on goose survival and overall growth rate. Our goals were to 1) estimate demographic parameters for Canada geese in five different regions in Nebraska; 2) estimate the effect of increasing daily bag limits during the early September season and regular season on survival of hatch-year, juvenile, and adult Canada geese; and 3) relate the effect of estimated changes in survival to regional growth rates. We found that survival (0.54–0.87), fidelity (0.14–0.99), and productivity (number of young per adult, 0.17–2.08) varied substantially among regions within Nebraska. We found that increasing early-season bag limits, but not regular-season bag limits, reduced survival in Canada geese. However, this effect was greatest when comparing years without an early season to years with the highest daily bag limits used in Nebraska (eight). Survival of juvenile geese (2–3 y posthatch) were unaffected by changes in daily bag limits during any season, though the probability of reporting was greatest for this age class. The observed reductions in survival probability of hatch-year and adult geese due to increased daily bag limits during the early season (< 10%) led to a decrease in regional growth rates of ∼5% between years with the most liberal early-season daily bag limits and years without an early season. Our results suggest that increased bag limits during the early season may reduce Canada goose survival, but not enough to affect regional growth rates in Nebraska.