Northern bobwhite subspecies exhibit reduced survival and reproduction when translocated outside their native range

The popularity of translocation as a conservation tool to reintroduce and re-stock existing populations of northern bobwhite (Colinus virginianus) to restored habitat has increased following decades-long decline; however, population sources are limited to a few areas in the United States where stable or increasing populations remain. Understanding how demographic parameters of translocated individuals vary by source region and subspecies will help increase the effectiveness of translocation as a recovery tool. Our objectives were to compare survival, movements, and reproduction of 2 translocated subspecies of bobwhite. We translocated 665 bobwhites (n = 253 northwest Texas [C. v. taylori]; n = 412 south Texas [C. v. texanus]) to an 890-ha site in northcentral Texas, USA, during March 2019-2021 and radio-marked 380 (n = 184 northwest Texas; n = 196 south Texas). The northwest subspecies is considered the subspecies native to the release site. Radio-marked bobwhites from south Texas were 1.25 times (95% CI = 0.98-1.60) more likely to die on the study site than individuals from northwest Texas. Home ranges (95% kernel density estimator) were larger for bobwhites sourced from northwest Texas (51 ha, 95% CI = 39-63 ha) compared to individuals from south Texas (32 ha, 95% CI = 22-42 ha). Individuals from northwest Texas were 1.5 times (95% CI = 1.10-1.80) more likely to leave the study site but 3.2 times (95% CI = 2.32-4.19) more likely to return to the study site after dispersing. Radio-marked bobwhites from northwest Texas produced 44% more nests per female than birds from south Texas. Managers who wish to use non-native subspecies of bobwhite to supplement a translocation effort should be cognizant of the potential reductions in survival and reproduction that may occur.

Automated summary

The popularity of translocation as a conservation tool has increased due to the decline in the population of northern bobwhite. However, population sources are limited to a few areas in the United States. Understanding the demographic parameters of translocated individuals will help increase the effectiveness of translocation as a recovery tool.