Survival and mortality of green‐winged teal banded on the Yukon‐Kuskokwim Delta, Alaska

Abstract

AbstractDespite the importance of green‐winged teal (Anas crecca) as a harvested species in North America, recent information on variation in vital rates among regions is lacking. We used band recovery data and hierarchical autoregressive models to examine temporal and age‐sex‐class variation in survival, hunting mortality, and nonhunting mortality probabilities of green‐winged teal banded at Kgun Lake on the Yukon‐Kuskokwim Delta, Alaska, USA, from 1997–2019. We used data from 10,554 adult and juvenile green‐winged teal of known sex and age banded and released at Kgun Lake, and 1,245 hunter recoveries. Estimates of annual survival probability for adult females and males ranged from 0.44 (95% CI = 0.29–0.54) to 0.49 (95% CI = 0.37–0.68) and 0.56 (95% CI = 0.50–0.61) to 0.58 (95% CI = 0.50–0.64), respectively, during our study period. Estimates of annual survival probability for juvenile females and males ranged from 0.36 (95% CI = 0.18–0.56) to 0.46 (95% CI = 0.31–0.71) and 0.51 (95% CI = 0.38–0.61) to 0.56 (95% CI = 0.44–0.71), respectively. Hunting mortality probability was greatest for juvenile males and least for adult females. Hunting mortality probability of juvenile males increased from 0.09 (95% CI = 0.05–0.13) in 1997 to 0.14 (95% CI = 0.11–0.18) in 2015. Nonhunting mortality probability was greater and more variable than hunting mortality probability for all age‐sex classes, indicating nonhunting mortality contributed most to total mortality of green‐winged teal banded at Kgun Lake during our study. Additionally, survival probability of female green‐winged teal banded at Kgun Lake is less than published estimates for green‐winged teal banded in the boreal forest of Alaska. We recommend continuing consistent banding operations for green‐winged teal on the Yukon‐Kuskokwim Delta and other important breeding areas to further understand factors influencing nonhunting mortality and how they may vary seasonally and geographically.