Chick and juvenile survival are important vital rates for population monitoring and making sound management decisions. These demographics are poorly understood in Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) and survival estimation in the first 2 weeks is particularly challenging to assess. In 2015-2017, we captured 1,219 chicks (1-7 days old) from 156 broods. We marked 625 chicks with radio-transmitters to monitor their survival and recaptured them to replace the radio-transmitter from 18-30 days old.Overall survival of chicks and juveniles for the brood-rearing season (initial capture-31 Aug) was 0.30 ± 0.02 (SE; 95% CI = 0.26, 0.35, n = 746) using the Kaplan-Meier product-limit estimator. We used Cox proportional hazards regression to model survival and for chicks entering the study at 2-4 days old, survival to 21 days old was 0.59 ± 0.03 (95% CI = 0.53, 0.65, n = 529) and increasing chick mass had a positive effect on chick survival probability, with a 6.0% decrease in mortality risk for each additional gram of mass at initial capture. Juvenile survival was 0.51 ± 0.04 (95% CI = 0.43, 0.60, n = 294) and differed by study site. Of our 4 study sites, the 2 western sites (West Axial, Iles Dome) had 65-80% greater hazard compared to the 2 more eastern sites (Routt, Trapper). Juvenile survival was also influenced by hatch date, with a 3.0% greater hazard for each day later in the nesting season that a nest hatched.

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Wildlife management and conservation can be challenging when the demography of a focal species is unknown or limited given that fecundity and adult survival influence population growth. The Columbian sharp‐tailed grouse (Tympanuchus phasianellus columbianus) have been reduced to ≤10% of their former range since the early 1900s. We conducted a 3‐year study (2015–2017) across 4 study sites in northwestern Colorado, USA, to evaluate female hazard and nest survival. We trapped and marked 270 female sharp‐tailed grouse and identified 275 nests for our hazard and survival analyses. Females during the breeding stage of the reproductive season experienced more hazard compared to the nesting and the early and late post‐nesting stages for females without broods. Females experienced a higher degree of hazard during the breeding stage and mortality risk was >3 times higher than the nesting stage, >7 times higher than early post‐nesting (EPN)‐no brood stage, and >5 times higher than the late post‐nesting (LPN)‐unsuccessful stage. Two reproductive season stages (LPN‐successful and EPN‐brood) provided marginal inference. Nest incubation initiation date and nest age best described nest daily survival. Females that initiated incubation of initial nests earlier in the season experienced lower nest daily survival than later in the incubation season. Because female Columbian sharp‐tailed grouse hazard varied among different reproductive season stages, we recommend that wildlife managers develop management actions that reduce hazard during the specific reproductive season stages (i.e., the breeding season). For Columbian sharp‐tailed grouse in Colorado, we recommend that Colorado Parks and Wildlife collaborate with federal farm program agencies to implement a no‐tillage restriction from 1 May through 30 June for active agricultural fields within 2 km of active Columbian sharp‐tailed grouse leks to enhance nest survival.

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