BARN OWL - FIELD BIOLOGY AND RAT CONTROL

摘要

Barn owls have been established in nest boxes of several cocoa, cocoa-coconut (in some interspersed oil palm) areas for rat control in UIE estates, Perak. Nest occupancy occurred within two months after establishment. The nests were used for breedingat two cycles per year. Radiotracking for 10 owls and leg banding of new adult owls were undertaken and more than 50 barn owls were tagged. Emitters have a life-span of 12 months, could be detected for 500 m but had problems despite back harnessing and antennae placement, Owls generally occupied the same nests and one tagged female was recorded for more than 23 months with 5 breeding cycles within the same nest. Growth, development and weight gains were similar to that noted in the laboratory, where fledging adults were around 500 g. Rat carcasses noted in the nests were mainly R. tiomanicus and field crop losses were low; indicating that at low rat population levels, bam owls could effectively control rats with minimal baiting after about 2 years.