Population ecology and conservation of the barn owl Tyto alba in farmland habitats in Liemers and Achterhoed (The Netherlands)

Published source details 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.
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This study is summarised as evidence for the following.

	Action	Category
	Provide owl nest boxes (Tawny owl, Barn owl) Action Link

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.