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Anticoagulant rodenticides (ARs) are used worldwide for the control of rodent pests and are the main method of control of rat pest populations in agricultural areas. The main aim of this review is to discuss the risk of ARs to non-target wildlife in oil palm areas in Southeast Asia, mainly Indonesia and Malaysia. We discussed AR use in oil palm areas and toxicities of ARs on target and non-target animals. We also reviewed published literature on wildlife species reported in oil palm areas in Southeast Asia and utilizing this information, we assessed the hazard risk of ARs to non-target wildlife in oil palm plantations. ARs are a secondary exposure hazard to rodent-consuming mammalian carnivores, such as leopard cats and civets, and rodent-consuming raptors, such as barn owls. Consumption of dead poisoned prey puts scavengers, such as water monitors, at high risk for AR exposure. Domestic livestock and granivorous birds are at high risk for AR exposure via primary exposure to toxic bait, while omnivores such as macaques and wild pigs are at moderate risk for both primary and secondary exposure to ARs. The effects of ARs on barn owls have been well studied in the field and in laboratory secondary toxicity studies. Thus, the nest-box occupancy and reproductive parameters of local barn owl populations can be monitored as an indicator of the AR exposure level in the area. Clinical Trials Registration: No clinical trials were involved in this study. [ABSTRACT FROM AUTHOR]

In Peninsular Malaysia, barn owls (Tyto javanica javanica) have been utilized as biological control of rats since the 1960s. In this study, the impact of introduced barn owls on rat populations in an oil palm plantation in Sabah, Malaysia, were studied. There were three treatment areas in this study: T1 (barn owl area) was an oil palm plot where no rodenticides were applied and rat control relied solely on predation of the introduced barn owls, T2 was an oil palm plot where one fixed baiting campaign was carried out per year, and T3 was an oil palm plot where two fixed baiting campaigns were carried out per year. Rat abundance and fresh fruit bunch (FFB) damage were assessed monthly throughout the four-year study period. The dominant species at all treatment areas was the House rat, Rattus rattus diardii. Both rat abundance and FFB damage were higher in the first year of study at all three treatment areas. FFB damage was lowest at T3 compared to the other two treatment areas throughout the entire study period, probably due to the intensive baiting carried out at T3. FFB damage at T1 was comparable to FFB damage at T2 (with the exception of the first year of study). Additionally, FFB damage at T1 after the first year was frequently below the 5% FFB damage threshold level. The results of this study indicate that introduced barn owl control of rat pests was sufficient for at least three years and perhaps more. [ABSTRACT FROM AUTHOR]