Northern Bobwhite Chick Survival and Effects of Weather

• Published in: The Journal of wildlife management 2019-05, Vol.83 (4), p.963-974
• Main Authors: TERHUNE, THERON M., PALMER, WILLIAM E., WELLENDORF, SHANE D.
• Format: Article
• Language: English
• Subjects: Annual variations; brood; Chickens; Chicks; Colinus virginianus; Data recovery; demographics; Ecological conditions; Juveniles; Limiting factors; live‐dead recovery; Marking; neonate; Population Ecology; Precipitation; precocial; Seasonal variations; Survival; temperature; Temperature effects; Weather; Wildlife management; Winter
• ISSN: 0022-541X; 1937-2817
• DOI: 10.1002/jwmg.21655

Reliable vital rates for all life stages are necessary to identify limiting factors in wildlife populations and inform sound wildlife management. The difficulty associated with capturing and tagging precocial young, such as northern bobwhite chicks (Colinus virginianus), and linking variation in recruitment to ecological conditions has contributed to significant knowledge gaps in their population ecology. During 1999–2017, we captured and patagial-tagged ≤12-day-old bobwhite chicks (n = 3,576) and estimated their survival from time of capture (Jun–Sep) to fall and winter (Nov and Jan) recapture and winter (Feb) recovery. We used Burnham’s model implemented in Program MARK to integrate mark-recapture and dead-recovery (via harvest) data to estimate survival for the 19-year study. By including weather covariates, we also evaluated explicit hypotheses related to temperature and precipitation effects on chick survival. We found inter-annual, intra-annual, and intra-seasonal variation in chick survival with an average annual daily survival estimate of 0.9887 (95% CI = 0.9321, 0.9918). Precipitation amount and number of precipitation (>0.635 cm) events during the first 4 weeks post-tagging decreased the daily survival rate of chicks curvilinearly. Average minimum daily temperature and maximum daily temperature effects on survival were negligible, but an interaction between minimum temperature and cumulative precipitation during the first 14 days post-tagging affected survival. We recommend population modelers incorporate intra- and inter-annual variation in chick survival to improve predictions. Observed variation in chick survival rates portends a significant opportunity to improve population management for bobwhites and other game birds.