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
Context. Nest predation is a leading cause of nest failure for most ground-nesting birds. Methods that allow for accurate classification of fate and identification of predators are important for understanding productivity and conservation strategies. Past studies have used a visual inspection of nest remains to determine nest fate and predict predator identity. Most formal assessments of these methods have addressed small-bodied birds nesting in trees or shrubs, and have revealed that use of evidence at nests can be relatively accurate for determining nest fate but may lead to incorrect conclusions regarding predator identity. However, few have tested the latter hypothesis for larger ground-nesting birds with precocial young. Aim. We aimed to evaluate a classification system developed for determining nest fate and identifying predators of waterfowl nests, at both the scale of individual nests and across the study area. Methods. From 2016 to 2020, we located 989 blue-winged teal (Spatula discors), mallard (Anas platyrhynchos) and gadwall (Mareca strepera) nests in central North Dakota. We placed cameras at a subset of 249 nests and recorded evidence of nest remains at depredated nests. Key results. The most common predators were American badgers (Taxidea taxus), followed by striped skunks (Mephitis mephitis), raccoons (Procyon lotor) and red foxes (Vulpes vulpes). Using evidence of nest remains, we determined nest fates with high accuracy (98.0%). However, evidence of nest remains was only sufficient for identifying predators at 50% of nests, and the classification system was correct only 69.7% of the time. The predicted proportion of predators across the study area differed between the classification system and our video evidence as well. Conclusions. The accuracy of predator identifications based upon the classification system that we evaluated was not supported at any scale. Implications. Our results suggest that evidence of nest remains can be used to determine nest fate for large-bodied precocial, ground-nesting birds, but accurate identification of nest predators will require alternative methods such as nest cameras.
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