The Evaluation of a Decade Barn Owl (Tyto alba) Introduction in Oil Palm Plantations Central Kalimantan

Abstract

The barn owls (Tyto alba), as a biological control for the rat population, are relatively effective and safe for the oil palm ecosystem. So nowadays, many oil palm plantations are trying to introduce it to reduce the use of rodenticides. This paper’s objective is to evaluate a decade of T. alba introduction in ca 80,000 ha oil palm plantations in Central Kalimantan since the initial releasing three pairs of T. alba in July 2011. We use a quantitative descriptive method to provide the primary data on a monthly monitoring basis, i.e., the T. alba population, including its chick and eggs; the number of barn owl boxes occupied; rat damage percentage and the number of rat baiting applications. The population increment during the year 2011 to 2012 was retarded. However, since the year 2013, the population of barn owl population rapidly increased using a combination of self-released barn owl distribution from field barn owl boxes. It assisted augmentation from barn owl hatchery methods. Based on the monthly census in December 2022, the occupancy rates reached 75% from 4,234 boxes; occupied by 6,390 owls, 1,665 chicks, and 1,531 eggs. The established population of T. alba in an oil palm plantation in Central Kalimantan has reduced the rat damage percentage below the threshold level of 5%. It has no rat-baiting application (zero rat bait).