Bird demographic responses to predator removal programs

Invasive predators pose a significant bird populations worldwide. Humans have a long.history of removing predators from ecosystems;.current island restoration actions typically focus on.the removal of invasive predators, such as non-native.rodents, from seabird breeding islands. While not.overly abundant, the results of predator removal.studies provide valuable information on the demographic.response of birds, and can assist conservation.practitioners with prioritizing invasive predator.removal projects. We review such studies focusing.on observed demographic responses of bird predator removal campaigns and whether.ecological factors are useful in predicting those.responses. From the 800? predator removal programs.indentified, a small fraction (n = 112) reported.demographic responses of bird populations. productivity was the most commonly reported.response, which on average increased by 25.3% (2.5.SE) with predator removal. The best supported model.for predicting the change in productivity from predator.removal incorporated bird body mass, egg mass,.predator type, nest type and an interaction term for.body mass and nest type (AICc weight = 0.457). The.predicted percent increase in productivity resulting.from hypothetical predator removal ranged from 63.0% (mean = 45.0, 5.6 SE), and was lowest for.large, surface nesting birds such as albatrosses. The.predicted increase in productivity resulting from.predator removal alone was insufficient to reverse.the predicted population decline for 30–67% of bird.species considered, suggesting that in many cases,.removal of predators must be performed in combination.with other conservation actions in order to ensure.a stable or increasing population..

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