Factors influencing reproductive performance of northern bobwhite in South Florida

Abstract

Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003-2008 to estimate reproductive parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10±0.22, but females laid more eggs in their first clutch (12.43±0.24) than in subsequent clutches (10.19± 0.53) within a nesting season. Daily nest survival was higher for first (0.966±0.003) than subsequent nests (0.936±0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853±0.008, but was higher for nests incubated by females (0.873±0.009) than those incubated by males (0.798±0.018). The proportion of individuals attempting a second nest was 0.112±0.024 and 0.281±0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation.

Northern bobwhite breeding season ecology on a reclaimed surface mine

“…Similarly, mean hatching success (85.5 ± 2.9%) was slightly lower than the population average reported by Sandercock et al (85–95%; ), and our estimates of re‐nesting and double‐clutching were exceptionally low; no males and only 13.8% of females ( n = 12) were known to re‐nest after a failed nesting attempt. Our re‐nesting rate was less than half of what was reported in a study from Florida (0.28; Rolland et al ) and below the range reported by Sandercock et al (25­–69%; ).…”

“…Our re-nesting rate was less than half of what was reported in a study from Florida (0.28; Rolland et al 2011) and below the range reported by Sandercock et al (25-69%;2008).…”

Assessing the sensitivity of avian species abundance to land cover and climate

“…In addition to range shifts, there is increasing evidence that climate is linked to avian survival and productivity (Rolland et al. , Skagen and Adams , Cox et al. , b , Jenouvrier ).…”

“…In addition to range shifts, there is increasing evidence that climate is linked to avian survival and productivity (Rolland et al 2011, Skagen and Adams 2012, Cox et al 2013a, b, Jenouvrier 2013. Dybala et al (2013) found a direct effect of winter temperature on adult survival and an indirect effect of prior rainy season on juvenile survival.…”

“…Migratory behavior may also play an important role in determining which species are affected by changes in climate (Albright et al 2010a, Both et al 2010, Rolland et al 2011, Salewski et al 2013. Winter severity is linked to the survival of resident and short-distance migrants (Salewski et al 2013), while long-distance migrants are affected more in seasonal habitats due to their sensitivity to droughts (Albright et al 2010b) and seasonal mismatches with food resources (Both et al 2010).…”