Incubation recess behaviors influence nest survival of Wild Turkeys

Abstract

In ground nesting upland birds, reproductive activities contribute to elevated predation risk, so females presumably use multiple strategies to ensure nest success. Identification of drivers reducing predation risk has primarily focused on evaluating vegetative conditions at nest sites, but behavioral decisions manifested through movements during incubation may be additional drivers of nest survival. However, our understanding of how movements during incubation impact nest survival is limited for most ground nesting birds. Using GPS data collected from female Eastern Wild Turkeys (n = 206), we evaluated nest survival as it relates to movement behaviors during incubation, including recess frequency, distance traveled during recesses, and habitat selection during recess movements. We identified 9,361 movements off nests and 6,529 recess events based on approximately 62,065 hr of incubation data, and estimated mean nest attentiveness of 84.0%. The numbers of recesses taken daily were variable across females (range: 1‒7). Nest survival modeling indicated that increased cumulative distance moved during recesses each day was the primary driver of positive daily nest survival. Our results suggest behavioral decisions are influencing trade‐offs between nest survival and adult female survival during incubation to reduce predation risk, specifically through adjustments to distances traveled during recesses.

Behavioral strategies during incubation influence nest and female survival of Wild Turkeys

“…We refined the approaches taken by Bakner et al. (2019) by relating daily incubation behaviors to nest and female survival, while also using a larger sample of females monitored across a broader temporal period. Our findings support the prediction that female wild turkeys use multiple strategies during incubation, presumably driven by life‐history trade‐offs between predation risk and reproductive success on a dynamic landscape.…”

“…Recently, Bakner et al. (2019) used a subsample of females monitored during our study to more coarsely assess influences of incubation behaviors on nest survival. The authors noted that cumulative distances traveled per day during incubation most influenced nest survival.…”

“…(2019) and Bakner et al. (2019), we defined recess movements as any GPS location >27.5 m from the nest coordinates, whereas GPS locations ≤27.5 m from the nest coordinates were considered as nest (incubation) locations. Previous studies have noted that space use may influence survival and reproductive success (Badyaev et al., 1996; Patrick & Weimerskirch, 2017; Yoder et al., 2004), and movements to and from nests may increase predation risk to parents and offspring (Martin, 2002; Wiebe & Martin, 1997).…”

“…We constructed a Bayesian hierarchical nest survival model (Royle & Dorazio, 2008) using the R2jags package (Su & Yajima, 2015) in R (R Core Team, 2019) to estimate nest survival. We parameterized models using covariates likely to influence survival of nests (Bakner et al., 2019; Lehman et al., 2008; Wiebe & Martin, 1997), which included daily distance traveled, unique recesses taken daily, recess duration, daily range size, and nest concealment. For most precocial avian species, older nests are more likely to survive because nests in riskier locations are depredated early (Klett & Johnson, 1982).…”

“…To expand upon earlier (Green, 1982; Williams et al., 1971) and more contemporary works describing incubation recess behaviors of wild turkeys (Bakner et al., 2019; Conley et al., 2015), our objectives were to (a) examine daily recess behaviors of incubating female Eastern wild turkeys and (b) relate incubation behaviors and nest concealment to nest and female survival to identify whether individual females used strategies to maximize nest success or survival. We hypothesized incubating females would prioritize productivity and survival individually, which would be reflected in differences in daily movements and space use.…”