Individual study: Population ecology and conservation of the barn owl Tyto alba in farmland habitats in Liemers and Achterhoed (The Netherlands)
de Bruin O (1994) Population ecology and conservation of the barn owl Tyto alba in farmland habitats in Liemers and Achterhoed (The Netherlands). Ardea, 82, 1-109
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Provide owl nest boxes (Tawny owl, Barn owl)
A study of 200 barn owl Tyto alba nest boxes over 10 years in the east of the Netherlands (de Bruin 1994) found that with increasing availability of boxes, over 90% of broods in the area became established in boxes and populations increased. Occupancy rates were 32% in Liemers and 36% in Achterhoek, although boxes were occupied significantly less frequently in Liemers (2.8 vs 4.5 years). Between 1967-1975, less than 25% of the barn owl broods in the area were in nest boxes, but with increasing availability, in 1976-1984 over 75% of broods and in 1985-1993 over 90% of broods were in boxes. The number of fledged young was significantly higher in nest boxes (3.4) compared to natural nest sites (2.5). In Leimers there was a significant decline in the breeding population from the early 1960s (7-20 breeding pairs/100 km²) to the end of the 1970s (2-3), the population then stabilized in the 1980s and increased in the 1990s (11-13). In Achterhoek, the population also decreased in the 1960s (to 3-5), but then increased from the 1970s (1976-1982: 5-8) through to the 1990s with increasing availability of nest boxes. In 1967-1984, 75 nest boxes were put up in suitable buildings in Liemers and 135 in Achterhoek. Boxes were surveyed in 1967-1993. Landscape structure and habitats differed in Liemers (350 km²) and Achterhoek (550 km²), which were either side of a river.